Interspinous process implants and methods of use

ABSTRACT

Systems and method in accordance with an embodiment of the present invention can includes an implant comprising a first wing, a spacer extending from the first wing, and a distraction guide. The distraction guide is arranged in a first configuration to pierce and/or distract tissue associated with adjacent spinous processes extending from vertebrae of a targeted motion segment. The implant can be positioned between the adjacent spinous processes and once positioned, the implant can be arranged in a second configuration. When arranged in a second configuration, the distraction guide can act as a second wing. The first wing and the second wing can limit or block movement of the implant along a longitudinal axis of the implant.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of each of U.S. patent applicationSer. Nos. 11/806,528 and 11/806,526, each entitled “Interspinous ProcessImplants and Methods of Use,” and filed May 31, 2007; each of which isincorporated herein by reference in its entirety.

Each of U.S. patent application Ser. Nos. 11/806,528 and 11/806,526 is acontinuation-in-part of U.S. patent application Ser. No. 10/694,103,entitled “Interspinous Process Implant with Radiolucent Spacer andLead-in Tissue Expander,” filed Oct. 27, 2003, which claims priority toU.S. Provisional Application Ser. No. 60/421,915, entitled “InterspinousProcess Implant with Radiolucent Spacer and Lead-in Tissue Expander,”filed Oct. 29, 2002; each of which is incorporated herein by referencein its entirety.

Each of U.S. patent application Ser. Nos. 11/806,528 and 11/806,526 is acontinuation-in-part of U.S. patent application Ser. No. 11/234,555,entitled “Interspinous Process Implant and Method of Implantation,”filed Sep. 23, 2005, which claims priority to U.S. ProvisionalApplication Ser. No. 60/612,582, entitled “Interspinous Process Implantand Method of Implantation,” filed Sep. 23, 2004 and which is acontinuation-in-part of U.S. patent application Ser. No. 10/850,267,entitled “Distractible Interspinous Process Implant and Method ofImplantation,” filed May 20, 2004, which claims priority to U.S.Provisional Application Ser. No. 60/472,817, entitled “CervicalInterspinous Process Implant and Method of Implantation,” filed May 22,2003; each of which is incorporated herein by reference in its entirety.

Each of U.S. patent application Ser. Nos. 11/806,528 and 11/806,526 is acontinuation-in-part of U.S. patent application Ser. No. 11/378,893,entitled “Interspinous Process Implant with Slide-in Distraction Pieceand Method of Implantation,” filed Mar. 17, 2006, which claims priorityto U.S. Provisional Application Ser. No. 60/664,311, entitled“Interspinous Process Implant with Slide-in Distraction Piece and Methodof Implantation,” filed Mar. 22, 2005 and which is acontinuation-in-part of U.S. patent application Ser. No. 10/850,267,entitled “Distractible Interspinous Process Implant and Method ofImplantation,” filed May 20, 2004, which claims priority to U.S.Provisional Application Ser. No. 60/472,817, entitled “CervicalInterspinous Process Implant and Method of Implantation,” filed May 22,2003; each of which is incorporated herein by reference in its entirety.

Each of U.S. patent application Ser. Nos. 11/806,528 and 11/806,526 is acontinuation-in-part of U.S. patent application Ser. No. 11/384,055,entitled “Interspinous Process Implant with Slide-in Distraction Pieceand Method of Implantation,” filed Mar. 17, 2006, which claims priorityto U.S. Provisional Application Ser. No. 60/664,049, entitled“Interspinous Process Implant with Slide-in Distraction Piece and Methodof Implantation,” filed Mar. 22, 2005 and which is acontinuation-in-part of U.S. patent application Ser. No. 10/850,267,entitled “Distractible Interspinous Process Implant and Method ofImplantation,” filed May 20, 2004, which claims priority to U.S.Provisional Application Ser. No. 60/472,817, entitled “CervicalInterspinous Process Implant and Method of Implantation,” filed May 22,2003; each of which is incorporated herein by reference in its entirety.

Each of U.S. patent application Ser. Nos. 11/806,528 and 11/806,526 is acontinuation-in-part of U.S. patent application Ser. No. 10/816,173,entitled “Cervical Interspinous Process Implant and Method ofImplantation,” filed Apr. 1, 2004, now U.S. Pat. No. 7,549,999, whichclaims priority to U.S. Provisional Application Ser. No. 60/472,817,entitled “Cervical Interspinous Process Implant and Method ofImplantation,” filed May 22, 2003; each of which is incorporated hereinby reference in its entirety.

Each of U.S. patent application Ser. Nos. 11/806,528 and 11/806,526 is acontinuation-in-part of U.S. patent application Ser. No. 11/095,440,entitled “Interspinous Process Implant Including a Binder and Method ofImplantation,” filed Mar. 31, 2005, which claims priority to U.S.Provisional Application Ser. No. 60/612,465, entitled “InterspinousProcess Implant Including a Binder and Method of Implantation,” filedSep. 23, 2004; each of which is incorporated herein by reference in itsentirety.

Each of U.S. patent application Ser. Nos. 11/806,528 and 11/806,526 is acontinuation-in-part of U.S. patent application Ser. No. 11/095,680,entitled “Interspinous Process Implant Including a Binder and Method ofImplantation,” filed Mar. 31, 2005, which claims priority to U.S.Provisional Application Ser. No. 60/612,465, entitled “InterspinousProcess Implant Including a Binder and Method of Implantation,” filedSep. 23, 2004; each of which is incorporated herein by reference in itsentirety.

Each of U.S. patent application Ser. Nos. 11/806,528 and 11/806,526 is acontinuation-in-part of U.S. patent application Ser. No. 11/378,108,entitled “Interspinous Process Implant Having Deployable Wing and Methodof Implantation,” filed Mar. 17, 2006, which claims priority to U.S.Provisional Application Ser. No. 60/663,918, entitled “InterspinousProcess Implant Having Deployable Wing and Method of Implantation,”filed Mar. 21, 2005; each of which is incorporated herein by referencein its entirety.

Each of U.S. patent application Ser. Nos. 11/806,528 and 11/806,526 is acontinuation-in-part of U.S. patent application Ser. No. 11/377,971,entitled “Interspinous Process Implant Having Deployable Wing and Methodof Implantation,” filed Mar. 17, 2006, which claims priority to U.S.Provisional Application Ser. No. 60/663,885, entitled “InterspinousProcess Implant Having Deployable Wing and Method of Implantation,”filed Mar. 21, 2005; each of which is incorporated herein by referencein its entirety.

Each of U.S. patent application Ser. Nos. 11/806,528 and 11/806,526 is acontinuation-in-part of U.S. patent application Ser. No. 11/378,894,entitled “Interspinous Process Implant Having Deployable Wing and Methodof Implantation,” filed Mar. 17, 2006, which claims priority to U.S.Provisional Application Ser. No. 60/664,076, entitled “InterspinousProcess Implant Having Deployable Wing and Method of Implantation,”filed Mar. 22, 2005; each of which is incorporated herein by referencein its entirety.

Each of U.S. patent application Ser. Nos. 11/806,528 and 11/806,526 is acontinuation-in-part of U.S. patent application Ser. No. 11/389,002,entitled “Interspinous Process Implant Having Deployable Wings andMethod of Implantation,” filed Mar. 24, 2006, which claims priority toU.S. Provisional Application Ser. No. 60/672,402, entitled “InterspinousProcess Implant Having Deployable Wings and Method of Implantation,”filed Apr. 18, 2005; each of which is incorporated herein by referencein its entirety.

Each of U.S. patent application Ser. Nos. 11/806,528 and 11/806,526 is acontinuation-in-part of U.S. patent application Ser. No. 11/378,892,entitled “Interspinous Process Implant Having A Thread-Shaped Wing andMethod of Implantation,” filed Mar. 17, 2006, which claims priority toU.S. Provisional Application Ser. No. 60/663,922, entitled “InterspinousProcess Implant Having Deployable Wings and Method of Implantation,”filed Mar. 21, 2005; each of which is incorporated herein by referencein its entirety.

BACKGROUND

The spinal column is a bio-mechanical structure composed primarily ofligaments, muscles, vertebrae and intervertebral disks. Thebio-mechanical functions of the spine include: (1) support of the body,which involves the transfer of the weight and the bending movements ofthe head, trunk and arms to the pelvis and legs, (2) complexphysiological motion between these parts, and (3) protection of thespinal cord and the nerve roots.

As the present society ages, it is anticipated that there will be anincrease in adverse spinal conditions which are characteristic of olderpeople. By way of example only, with aging comes an increase in spinalstenosis (including, but not limited to, central canal and lateralstenosis), and facet arthropathy. Spinal stenosis results in a reductionforaminal area {i.e., the available space for the passage of nerves andblood vessels) which compresses the cervical nerve roots and causesradicular pain. Humpreys, S. C. et al, Flexion and traction effect onC5-C6 foraminal space, Arch. Phys. Med. Rehabil., vol. 79 at 1105(September 1998). Another symptom of spinal stenosis is myelopathy,which results in neck pain and muscle weakness. Id. Extension andipsilateral rotation of the neck further reduces the foraminal area andcontributes to pain, nerve root compression and neural injury. Id.; Yoo,J. U. et al., Effect of cervical spine motion on the neuroforaminaldimensions of human cervical spine, Spine, vol. 17 at 1131 (Nov. 10,1992). In contrast, neck flexion increases the foraminal area. Humpreys,S. C. et al, at 1105.

Pain associated with stenosis can be relieved by medication and/orsurgery. It is desirable to eliminate the need for major surgery for allindividuals, and in particular, for the elderly.

Accordingly, a need exists to develop spine implants that alleviate paincaused by spinal stenosis and other such conditions caused by damage to,or degeneration of, the spine. Such implants would distract, or increasethe space between, the vertebrae to increase the foraminal area andreduce pressure on the nerves and blood vessels of the spine. A furtherneed exists for development of a minimally invasive surgicalimplantation method for spine implants that preserves the physiology ofthe spine.

Further, a need exists for an implant that accommodates the distinctanatomical structures of the spine, minimizes further trauma to thespine, and obviates the need for invasive methods of surgicalimplantation. Additionally, a need exists to address adverse spinalconditions that are exacerbated by spinal extension and/or flexion.

SUMMARY

Systems and method in accordance with an embodiment of the presentinvention can includes an implant comprising a first wing, a spacerextending from the first wing, and a distraction guide. The distractionguide is arranged in a first configuration to pierce and/or distracttissue associated with adjacent spinous processes extending fromvertebrae of a targeted motion segment. The implant can be positionedbetween the adjacent spinous processes and once positioned, the implantcan be arranged in a second configuration. When arranged in a secondconfiguration, the distraction guide can act as a second wing. The firstwing and the second wing can limit or block movement of the implantalong a longitudinal axis of the implant.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1 a-1 f. FIG. 1 a is a front plan view of an embodiment of anassembled implant of the invention; FIG. 1 b is a left side view of theembodiment of the invention of FIG. 1 a; FIG. 1 e is a front plan viewof the embodiment of the invention of FIG. 1 a including a spacer, amain body and a first wing; FIG. 1 d is a left side view of the secondwing of the embodiment of the invention of FIG. 1 a; FIG. 1 e is a frontplan view of the second wing of the embodiment of the invention of FIG.1 a; FIG. 1 f is an end view of the spacer of the embodiment of theinvention of FIG. 1 a.

FIG. 2 a is a perspective view of an embodiment of the frame of thetissue expander or distraction guide of the invention. FIG. 2 b is aperspective view of an embodiment of the lead-in tissue expander ordistraction guide of the invention.

FIGS. 3 a and 3 b are an end and a perspective view of still anotherembodiment of the spacer of the invention. FIG. 3 c is a front view ofthe spacer of FIG. 3 a.

FIGS. 4 a and 4 b are an end and a perspective view of yet anotherembodiment of the spacer of the invention.

FIGS. 5 a and 5 b are an end and a perspective view of still anotherembodiment of the spacer of the invention.

FIGS. 6 a and 6 b are an end and a perspective view of a furtherembodiment of the spacer of the invention.

FIG. 7 is a perspective view of an embodiment of an implant inaccordance with the present invention having a spacer, a distractionguide, and a wing with an elliptical cross-section.

FIG. 8 is an end view of the implant of FIG. 7.

FIG. 9 is a perspective view of another embodiment of an implant inaccordance with the present invention having a wing with ateardrop-shaped cross-section.

FIG. 10 is an end view of a second wing for use with the implant of FIG.9.

FIG. 11 is a perspective view of an embodiment of an implant inaccordance with the present invention having a rotatable spacer and awing with an elliptical cross-section.

FIG. 12 is a perspective view of an embodiment of an implant inaccordance with the present invention having a rotatable spacer with twowings that are teardrop-shaped in cross-section.

FIG. 13 depicts the axis of rotation of the implant of FIG. 6 as seenfrom an end view.

FIG. 14 is a perspective view of an embodiment of an implant inaccordance with the present invention having a wing that is truncated ata posterior end.

FIG. 15A is an end view of an embodiment of an implant in accordance thepresent invention having a wing truncated at a posterior end and arotatable spacer.

FIG. 15B is a truncated second wing for use with the implant of FIG.15A.

FIG. 16 is a plan view of an embodiment of an implant in accordance withthe present invention wherein a screw is used to secure a second wing tothe spacer.

FIG. 17 is a perspective view of the second wing of FIG. 16.

FIG. 18 is a perspective view of the implant of FIG. 16.

FIG. 19A is a front view of a second wing for use with some embodimentsof implants of the present invention having a flexible hinge mechanismfor securing the second wing to an implant.

FIG. 19B is a side-sectional view of the second wing of FIG. 19A.

FIG. 20A is a plan view of an embodiment of an implant for use with thesecond wing of FIGS. 19A and 19B.

FIG. 20B is a front view of the second wing of FIGS. 19A and 19B.

FIG. 21A is a top view of an embodiment of an implant in accordance withthe present invention positioned between the spinous processes ofadjacent cervical vertebrae.

FIG. 21B is a top view of the implant of FIG. 21A.

FIG. 22 is a top view of two such implants of the invention as seen inFIG. 21, positioned in the cervical spine.

FIG. 23 is a side view of two implants of the invention positioned inthe cervical spine, with stops or keeps at the distal ends of thespinous processes.

FIG. 24 is a perspective view of an alternative embodiment of an implantfor use with systems and methods of the present invention.

FIG. 25A is an end view of an implant in accordance with still anotherembodiment of the present invention having a first part shaped toconform roughly with a contact surface of the spinous process.

FIG. 25B is a cross-sectional view of a spacer and a distracting insertin accordance with one embodiment of the present invention.

FIG. 25C is a cross-sectional view of a spacer and a distracting insertin accordance with an alternative embodiment of the present invention.

FIG. 25D is a cross-sectional view of a spacer and a distracting insertin accordance with still another embodiment of the present invention.

FIG. 26A is a front view of the implant of FIG. 24 inserted betweenspinous processes.

FIG. 26B is a front view of the implant of FIG. 26A having a distractinginsert positioned within cavities of the implant.

FIG. 27A is a cross-sectional side view of the implant of FIG. 24showing a distracting insert partially inserted in a cavity of theimplant having pins for aligning a first portion with a second portion.

FIG. 27B is a top view of the implant of FIG. 27A showing positioning ofpins for alignment of the first part and second part.

FIG. 28A is a perspective view of an alternative embodiment of animplant for use with systems and methods of the present invention,wherein the distracting insert includes a clip.

FIG. 28B is a side view of the implant of FIG. 28A showing a distractinginsert mated with the implant.

FIG. 28C is a side view of an alternative embodiment of an implant matedwith an alternative embodiment of a distracting insert.

FIG. 28D is a side view of still another embodiment of an implant matedwith still another embodiment of a distracting insert.

FIG. 29 is a perspective view of an embodiment of a distractible implantin accordance with the present invention having a second wing forlimiting or blocking shifting along the longitudinal axis.

FIG. 30 illustrates an embodiment of a method for implanting aninterspinous implant in accordance with the present invention.

FIG. 31 illustrates an alternative embodiment of a method for implantingan interspinous implant in accordance with the present invention.

FIG. 32 is a perspective view of an interspinous implant capable oflimiting or blocking relative movement of adjacent spinous processesduring extension of the spine.

FIG. 33A is a posterior view of the implant of FIG. 32 positionedbetween adjacent spinous processes.

FIG. 33B is a cross-sectional side view of a spacer of the interspinousimplant of FIGS. 32 and 33A positioned between spinous processes.

FIG. 33C is a cross-sectional view of the spacer of FIG. 33B duringflexion of the spine.

FIG. 34A is a side view of an embodiment of an implant in accordancewith the present invention having a distraction guide, a spacer, abrace, and a binder associated with the brace and fixable in position bya capture device.

FIG. 34B is a side view of an alternative embodiment of an implant inaccordance with the present invention including a brace wall havingrecesses for receiving lobes of a capture device.

FIG. 34C is a side view of still another embodiment of an implant inaccordance with the present invention including a capture device havinga spring-loaded cam for securing a binder against a brace wall.

FIG. 34D is a side view of a still further embodiment of an implant inaccordance with the present invention including a capture device havingdual spring-loaded cams for securing a binder in position.

FIG. 35A is an end view of the implant of FIG. 34A positioned betweenadjacent spinous processes.

FIG. 35B is an end view of the implant of FIG. 34A positioned betweenadjacent spinous processes.

FIG. 35C is an end view of the implant of FIG. 34A positioned betweenadjacent spinous processes wherein the spinous processes are surgicallymodified to receive a binder.

FIG. 36 is an end view of an alternative embodiment of an implant inaccordance with the present invention having a binder that varies inshape along the binder's length.

FIG. 37A is an end view of the implant of FIG. 36 positioned betweenadjacent spinous processes.

FIG. 37B is an opposite end view of the implant of FIG. 37A.

FIG. 37C is an end view of still another embodiment of an implant inaccordance with the present invention having a cord for a binder.

FIG. 38A is a side view of an embodiment of an implant in accordancewith the present invention including a wing associated with thedistraction guide to further limit or block movement of the implant.

FIG. 38B is a partial cross-sectional side view of an alternativeembodiment of an implant in accordance with the present inventioninclude an extendable wing associated with the distraction guide, theextendable wing being in a retracted position.

FIG. 38C is a partial cross-sectional side view of the implant of FIG.38B wherein the extendable wing is in an extended position.

FIG. 38D is a partial cross-sectional side view of still anotherembodiment of an implant in accordance with the present inventionincluding a spring-loaded wing associated with the distraction guide,the wing being in an extended position.

FIG. 38E is a partial cross-sectional side view of the implant of FIG.38D wherein the spring-loaded wing is in a collapsed position.

FIG. 39 is a top view of two implants in accordance with an embodimentof the present invention positioned between the spinous processes ofadjacent vertebrae, one of the implants having a binder arranged aroundthe adjacent spinous processes.

FIG. 40A is a perspective view of a further embodiment of an implant inaccordance with the present invention having a distraction guide, aspacer, a brace, and a binder associated with the brace and fixable inposition by a capture device.

FIG. 40B is a perspective view the implant of FIG. 40A wherein thecapture device is arranged to secure a binder between the capture deviceand the brace.

FIG. 40C is a side view of the implant of FIGS. 40A and 40B.

FIG. 41A is a cross-sectional top view of a binder loosely positionedwithin the capture device of the implant of FIGS. 40A and 40B.

FIG. 41B is a cross-sectional top view of the binder secured to thebrace by the capture device of the implant of FIGS. 40A and 40B.

FIG. 41C is a cross-sectional top view of a binder loosely positionedwithin an alternative embodiment of a capture device of the implant ofFIGS. 40A and 40B.

FIG. 41D is a cross-sectional top view of the binder and capture deviceof FIG. 41C wherein the binder is secured to the brace.

FIG. 42 is an end view of the implant of FIGS. 40A and 40B positionedbetween adjacent spinous processes.

FIG. 43 is a block diagram illustrating a method of positioning theimplant of FIG. 40A between adjacent spinous processes.

FIG. 44A is a perspective view of an still another embodiment of animplant in accordance with the present invention having a distractionguide, a spacer, a first wing, and a second wing including a capturedevice.

FIG. 44B is a perspective view of the implant of FIG. 44A in accordancewith the present invention having a distraction guide, a spacer, a firstwing, and a second wing including a capture device.

FIG. 45 is a perspective view of an still another embodiment of animplant in accordance with the present invention having a distractionguide, a spacer, a first wing, and a second wing including a capturedevice.

FIG. 46 is a perspective view of an still another embodiment of animplant in accordance with the present invention having a distractionguide, a spacer, a first wing, and a second wing including a capturedevice.

FIG. 47 is a block diagram illustrating a method of positioning theimplant of FIGS. 44A-46 between adjacent spinous processes.

FIG. 48A is a perspective view of an implant including a spacer having atear-drop shaped cross-section, a distraction guide, a first wing, and asecond wing connectable with the distraction guide.

FIG. 48B is a perspective view of an implant including a rotatablespacer having an elliptical cross-section, a distraction guide, a firstwing, and a second wing connectable with the distraction guide.

FIG. 49A is a perspective view of an implant in accordance with anembodiment of the present invention including a main body and an insert,the main body having a distraction guide, a spacer, and a first wing.

FIG. 49B is a perspective view of the implant of FIG. 49A wherein theinsert is positioned within the main body, causing the distraction guideassociated with the main body to limit or block movement of the implantwhen positioned between adjacent spinous processes.

FIG. 50A is a side view of the main body of the implant of FIGS. 49A and49B positioned between adjacent spinous processes.

FIG. 50B is a side view of the implant of FIG. 50A wherein the insert ispositioned within the main body.

FIG. 51 is a perspective view of an implant in accordance with analternative embodiment wherein the main body includes hooks to limitrelative movement of adjacent spinous processes during flexion motion.

FIG. 52 is a side view of the implant of FIG. 51 positioned betweenadjacent spinous processes and arranged so that the hooks confine theadjacent spinous processes.

FIG. 53A is a perspective view of still another embodiment of an implantin accordance with the present invention, wherein a first section and asecond section of a distraction guide are deployable to form a secondwing.

FIG. 53B is a perspective view of the implant of FIG. 53A wherein theinsert is positioned within the main body, causing the first section andthe second section of the distraction guide to deploy.

FIG. 54A is a perspective view of a still further embodiment of animplant in accordance with the present invention including a rotatablespacer.

FIG. 54B is a perspective view of the implant of FIG. 54A wherein theinsert is positioned within a central body so that the distraction guidedeploys as a second wing.

FIG. 54C is a cross-sectional side view of distraction guide of FIG.54A.

FIG. 54D is a cross-sectional side view of distraction guide of FIG.54B.

FIG. 55 is a side view of the implant of FIGS. 54A-54D positionedbetween adjacent spinous processes.

FIG. 56A is a side view of an alternative embodiment of the implantpositioned between adjacent spinous processes.

FIG. 56B is a partial cross-section side view of the implant of FIG. 56Ashowing deployable winglets disposed within a distraction guide of theimplant.

FIG. 56C is a partial cross-sectional side view of the implant of FIG.56B wherein the winglets deployed.

FIG. 57A is a side view of an alternative embodiment of the implantpositioned between adjacent spinous processes.

FIG. 57B is a side view of the implant of FIG. 57A positioned betweenadjacent spinous processes wherein the winglets deployed.

FIG. 57C is a partial cross-sectional end view of the implant of FIG.57A showing deployable winglets disposed within a distraction guide ofthe implant.

FIG. 57D is a partial cross-sectional end view of the implant of FIGS.57A-57C showing the winglets deployed so that the winglets extend fromthe distraction guide of the implant.

FIG. 57E is an end view of the implant of FIGS. 57A-57D showing thedistraction guide and the deployed winglets relative to the distractionguide.

FIG. 58A is a partial cross-sectional end view of an alternativeembodiment of an implant in accordance with the present inventionincluding an alternative actuator arrangement.

FIG. 58B is an partial cross-sectional end view of the implant of FIG.58A showing the winglets deployed so that the winglets extend from thedistraction guide of the implant.

FIG. 59A is a partial cross-sectional end view of still anotherembodiment of an implant in accordance with the present invention havingan alternative actuator arrangement wherein the winglets comprise twohinged portions.

FIG. 59B is a partial cross-sectional end view of the implant of FIG.59A showing the winglets deployed so that the winglets extend from thedistraction guide of the implant.

FIG. 60 is a partial cross-sectional end view of a still furtherembodiment of an implant in accordance with the present inventionwherein implants are arranged at adjacent motion segments.

FIG. 61 illustrates an embodiment of a method for implanting the implantof FIGS. 49A-55 between adjacent spinous processes in accordance withthe present invention.

FIG. 62 illustrates an embodiment of a method for implanting theinterspinous implant of FIGS. 49A-55 between adjacent spinous processesin accordance with the present invention.

FIG. 63 illustrates an embodiment of a method for implanting theinterspinous implant of FIGS. 56A-60 between adjacent spinous processesin accordance with the present invention.

FIG. 64A is a perspective view of an alternative embodiment of animplant in accordance with the present invention having a first wing anda second wing that can be deployed after arranging the implant betweenadjacent spinous processes.

FIG. 64B is a perspective view of the implant of FIG. 64A in a deployedconfiguration.

FIG. 65A is a posterior view of the implant of FIGS. 64A and 64Bpositioned between adjacent spinous processes in an undeployedconfiguration.

FIG. 65B is a posterior view of the implant of FIGS. 64A and 64Bpositioned between adjacent spinous processes in a deployedconfiguration.

FIG. 66A is a perspective view of still another embodiment of an implantin accordance with the present invention having a first wing and asecond wing that can be deployed after arranging the implant betweenadjacent spinous processes.

FIG. 66B is a perspective view of the implant of FIG. 66A in a deployedconfiguration.

FIG. 67 is a posterior view of the implant of FIGS. 66A and 66Bpositioned between adjacent spinous processes in a deployedconfiguration.

FIG. 68A is a perspective view of an alternative embodiment of animplant in accordance with the present invention having a first wing anda second wing that can be deployed after arranging the implant betweenadjacent spinous processes.

FIG. 68B is a perspective view of the implant of FIG. 68A in a partiallydeployed configuration.

FIG. 68C is a perspective view of the implant of FIG. 68A in a fullydeployed configuration.

FIG. 69A is a perspective view of the implant of FIG. 68A including acannula within which the implant is disposed for insertion into desiredlocation between adjacent spinous processes.

FIG. 69B is a perspective view of the implant of FIG. 69A in a partiallydeployed configuration.

FIG. 69C is a perspective close-up view of the implant of FIG. 69Ashowing hinged structures connected by cords.

FIG. 70 illustrates an embodiment of a method for implanting aninterspinous implant as shown in FIGS. 7-23 in accordance with thepresent invention.

FIG. 71 illustrates an embodiment of a method for implanting aninterspinous implant as shown in FIGS. 64A-67 having deployable firstand second wings in accordance with the present invention.

FIG. 72 illustrates an alternative embodiment of a method for implantingan interspinous implant as shown in FIGS. 68A-69B having deployablefirst and second wings by way of a cannula inserted between adjacentspinous processes in accordance with the present invention.

FIG. 73A is a perspective view of an implant including a spacer having atear-drop shaped cross-section, a distraction guide, a first wing, and asecond wing connectable with the distraction guide.

FIG. 73B is a perspective view of an implant including a rotatablespacer having an elliptical cross-section, a distraction guide, a firstwing, and a second wing connectable with the distraction guide.

FIG. 74A is a perspective view of a frame of an implant in accordancewith an embodiment of the present invention.

FIG. 74B is a perspective view of a spacer for use with the frame ofFIG. 74A.

FIG. 74C is a perspective view of the spacer of FIG. 74B seated withinthe frame of FIG. 74A.

FIG. 75A is a partial cross-sectional posterior view of the frame of theimplant of FIGS. 74A-74C positioned adjacent to an interspinous ligamentdisposed between adjacent spinous processes.

FIG. 75B partial cross-sectional posterior view of the frame of theimplant of FIGS. 74A-74C rotated so that the interspinous ligament isdisposed between a portion of the helical shaped second wing and thefirst wing along a longitudinal axis of the implant.

FIG. 75C partial cross-sectional posterior view of the frame of theimplant of FIGS. 74A-74C rotated so that the interspinous ligament isdisposed between the entire helical shaped second wing and the firstwing along the longitudinal axis.

FIG. 75D partial cross-sectional posterior view of the frame of theimplant of FIGS. 74A-74C wherein a spacer is partially arranged over acentral body of the frame so that a portion of the spacer partiallydistracts the interspinous ligament.

FIG. 75E partial cross-sectional posterior view of the frame of theimplant of FIGS. 74A-74C wherein the spacer is seated over the centralbody of the frame so that a portion of the spacer partially distractsthe interspinous ligament.

FIG. 76A is an end view of the implant of FIG. 75E positioned betweenadjacent spinous processes.

FIG. 76B is an front view of the implant of FIG. 75E positioned betweenadjacent spinous processes.

FIG. 77A is a perspective view of a frame from an alternative embodimentof an implant in accordance the present invention.

FIG. 77B is a perspective view of a spacer for use with the frame ofFIG. 77A.

FIG. 77C is a perspective view of the spacer of FIG. 77B seated withinthe frame of FIG. 77A.

FIG. 78 is a side view of the implant of FIGS. 77A-77C positionedbetween adjacent spinous processes.

FIG. 79A is a perspective view of a frame from a still furtherembodiment of an implant in accordance with the present invention.

FIG. 79B is a side view of the frame of FIG. 79A positioned betweenadjacent spinous processes.

FIG. 79C is a side view of the frame of FIG. 79A positioned betweenadjacent spinous processes and retracted to collapse the second wing.

FIG. 80 is a perspective view of a frame from a still further embodimentof an implant in accordance with the present invention.

FIG. 81 illustrates an embodiment of a method for implanting aninterspinous implant between adjacent spinous processes of the cervicalregion in accordance with the present invention.

FIG. 82 is a flowchart of a method for implanting an interspinousimplant between adjacent spinous processes of the lumbar region inaccordance with the present invention.

FIG. 83 is a perspective view of an alternative embodiment of an implantfor use with systems and methods of the present invention, the implantincluding an distraction piece mated with a initiating piece.

FIG. 84A is a perspective view of the initiating piece of the implant ofFIG. 83.

FIG. 84B is a perspective view of a proximal end of an insertion toolhaving prongs positioned within cavities of the initiating piece.

FIG. 84C is a perspective view of the prongs arranged in a lockedposition within the cavities of the initiating piece.

FIGS. 85A-85D are posterior views of the initiating piece of FIG. 84A asthe initiating piece is urged into position with the interspinousligament disposed between a lower portion of first wing and a lowerportion of the second wing.

FIG. 86 is a perspective view of the slide-in distraction piece of theimplant of FIG. 83.

FIGS. 87A-87D are posterior views showing the slide-in distraction pieceof FIG. 86 mating with the initiating piece positioned as shown in FIG.85D so that an implant as shown in FIG. 83 is disposed between theadjacent spinous processes.

FIG. 88A is a perspective view of an alternative embodiment of animplant for use with systems and methods of the present invention, theimplant including an distraction piece mated with a initiating piece.

FIG. 88B is a perspective view of the implant of FIG. 88A, the implantincluding an distraction piece mated with a initiating piece.

FIGS. 89A-89C are posterior views of the initiating piece of FIG. 88A asthe initiating piece is urged in position with the interspinous ligamentdisposed between the first wing and the second wing.

FIGS. 89D and 89E are posterior views showing the distraction piece ofFIG. 88A urged so that the distraction piece is mated with theinitiating piece.

FIG. 90 illustrates an embodiment of a method in accordance with thepresent invention for implanting the interspinous implant of FIG. 83.

FIG. 91 illustrates an embodiment of a method in accordance with thepresent invention for implanting the interspinous implant of FIG. 88A.

DETAILED DESCRIPTION

The following description is presented to enable any person skilled inthe art to make and use the invention. Various modifications to theembodiments described will be readily apparent to those skilled in theart, and the principles defined herein can be applied to otherembodiments and applications without departing from the spirit and scopeof the present invention as defined by the appended claims. Thus, thepresent invention is not intended to be limited to the embodimentsshown, but is to be accorded the widest scope consistent with theprinciples and features disclosed herein. To the extent necessary toachieve a complete understanding of the invention disclosed, thespecification and drawings of all patents and patent applications citedin this application are incorporated herein by reference.

An embodiment of an implant 100 of the invention is depicted in FIG. 1a.

This implant 100 includes a first wing 104 and a spacer 150 and alead-in tissue expander or distraction guide 110. This embodimentfurther can include, as required, a second wing 132. As can be seen inFIG. 1 a, a shaft 102 extends from the first wing 104 and is the bodythat connects the first wing 104 to the tissue expander or distractionguide 110. Also, as can be seen in FIGS. 1 a and 1 b, the distractionguide 110 in this particular embodiment acts to distract the soft tissueand the spinous processes when the implant 100 is inserted betweenadjacent spinous processes. In this particular embodiment, the guide 110has an expanding cross-section from the distal end 111 to the area wherethe second wing 132 is secured to the guide 110. In this embodiment theguide 110 is wedge-shaped.

Additionally, as can be seen in FIGS. 1 a and 1 f, the spacer 150 iselliptical-shaped in cross-section. The spacer 150 can have other shapessuch as circular, oval, ovoid, football-shaped, and rectangular-shapedwith rounded corners and other shapes, and be within the spirit andscope of the invention. In this preferred embodiment, the spacer 150includes a bore 152 which extends the length of the spacer 150. Thespacer 150 is received over the shaft 102 of the implant 100 and canrotate thereon about the shaft 102. In these embodiments, the spacer 150can have minor and major dimensions as follows:

Minor Dimension (116a) Major Dimension (116b)  6 mm 13.7 mm  8 mm 14.2mm 10 mm 15.2 mm 12 mm 16.3 mm 14 mm 17.8 mm

The advantage of the use of the spacer 150 as depicted in the embodimentof FIG. 1 a, is that the spacer 150 can be rotated and repositioned withrespect to the first wing 104, in order to more optimally position theimplant 100 between spinous processes. It is to be understood that thecortical bone or the outer bone of the spinous processes is stronger atan anterior position adjacent to the vertebral bodies of the vertebrathan at a posterior position distally located from the vertebral bodies.Also, biomechanically for load bearing, it is advantageous for thespacer 150 to be close to the vertebral bodies. In order to facilitatethis and to accommodate the anatomical form of the bone structures, asthe implant is inserted between the spinous processes and/or urgedtoward the vertebral bodies, the spacer 150 rotates relative to thewings, such as wing 104, so that the spacer 150 is optimally positionedbetween the spinous processes, and the wing 104 is optimally positionedrelative to the spinous processes. Further, the broad upper and lowersurfaces of the spacer 150 helps spread the load that the spinousprocesses place on the spacer 150.

As may be required for positioning the implant 100 between the spinousprocesses, the implant 100 can also include a second wing 132 which fitsover the guide 110 and is secured by a bolt 130 placed through anaperture 134 provided in a tongue 136 of second wing 132. The bolt 130is received and secured in the threaded bore 112 located in the guide110. As implanted, the first wing 104 is located adjacent to first sidesof the spinous processes and the second wing 132 is located adjacent tosecond sides of the same spinous processes.

In another embodiment, the spacer 150 has a cross-section with a majordimension and a minor dimension, wherein the major dimension is greaterthan the minor dimension, and, for example, less than about two timesthe minor dimension.

It is to be understood that the spacer 150 can be fabricated fromsomewhat flexible and/or deflectable material.

In this embodiment the spacer is made out of a polymer, morespecifically, the polymer is a thermoplastic. Still more specifically,the polymer is a polyketone known as polyetheretherketone (PEEK). Stillmore specifically, the material is PEEK 450G, which is an unfilled PEEKapproved for medical implantation available from Victrex of Lancashire,Great Britain. (Victrex is located at www.matweb.com or see Boedekerwww.boedeker.com). Other sources of this material include Gharda locatedin Panoli, India (www.ghardapolymers.com). The spacer 150 can be formedby extrusion, injection, compression molding and/or machiningtechniques. This material has appropriate physical and mechanicalproperties and is suitable for carrying and spreading the physical loadbetween the spinous process. Further in this embodiment, the PEEK hasthe following additional approximate properties:

Property Value Density 1.3 g/cc Rockwell M 99 Rockwell R 126 TensileStrength 97 MPa Modulus of Elasticity 3.5 GPa Flexural Modulus 4.1 GPa

In a preferred embodiment, the implant 100 is comprised in part oftitanium or other suitable implant material which may be radiopaque andin part of a radiolucent material that does not show up under x-ray orother type of imaging. In a preferred embodiment, the first and secondwings and the shaft are comprised of such a radiopaque material such astitanium and the spacer and the distraction guide or tissue expander arecomprised of a radiolucent material such as, for example, PEEK or PEKKor other radiolucent materials described herein. In an embodiment whichincludes the first wing, the spacer and the tissue expander, underimaging, the implant looks like an “T”. In an embodiment which includesboth a first and a second wing, the spacer and the tissue expander,under imaging, the implant looks like a “H”. This embodiment allows thedoctor to have a clearer view of the spine under imaging without theimplant interfering as much with the view of the bone structure.

It should be noted that the material selected may also be filled. Forexample, other grades of PEEK are also available and contemplated, suchas 30% glass-filled or 30% carbon-filled, provided such materials arecleared for use in implantable devices by the FDA, or other regulatorybody. Glass-filled PEEK reduces the expansion rate and increases theflexural modulus of PEEK relative to that which is unfilled. Theresulting product is known to be ideal for improved strength, stiffness,or stability. Carbon-filled PEEK is known to enhance the compressivestrength and stiffness of PEEK and lower its expansion rate.Carbon-filled PEEK offers wear resistance and load carrying capability.

In this embodiment, as described above, the spacer 150 is manufacturedfrom polyetheretherketone (PEEK), available from Victrex. As will beappreciated, other suitable similarly biocompatible thermoplastic orthermoplastic polycondensate materials that resist fatigue, have goodmemory, are flexible, and/or deflectable, have very low moistureabsorption, and good wear and/or abrasion resistance, can be usedwithout departing from the scope of the invention. The spacer can alsobe comprised of polyetherketoneketone (PEKK).

Other material that can be used include polyetherketone (PEK),polyetherketoneetherketoneketone (PEKEKK), andpolyetheretherketoneketone (PEEKK), and generally apolyaryletheretherketone. Further, other polyketones can be used as wellas other thermoplastics. The spacer can also be made of titanium.

Reference to appropriate polymers that can be used in the spacer can bemade to the following documents, all of which are incorporated herein byreference. These documents include: PCT Publication WO 02/02158 A1,dated Jan. 10, 2002, entitled “Bio-Compatible Polymeric Materials;” PCTPublication WO 02/00275 A1, dated Jan. 3, 2002, entitled “Bio-CompatiblePolymeric Materials;” and, PCT Publication WO 02/00270 A1, dated Jan. 3,2002, entitled “Bio-Compatible Polymeric Materials.”

Other materials such as Bionateg, polycarbonate urethane, available fromthe Polymer Technology Group, Berkeley, Calif., may also be appropriatebecause of the good oxidative stability, biocompatibility, mechanicalstrength and abrasion resistance. Other thermoplastic materials andother high molecular weight polymers can be used.

FIG. 2 a and FIG. 2 b shown an embodiment of the distraction guide ortissue expander 110. FIG. 2 a shows a frame 200 for a distraction guide110. The frame 200 is typically manufactured from radiopaque materialsuch as titanium. The frame 200 has a first end 202 and a second end204. The first end 202 has a shaft 102 which can be threaded withthreads 234 at one end to facilitate connection to, for example, a firstwing 104. The remaining end of the shaft connects to a distraction headframe 230 for the distraction guide 110. Alternatively, the shaft 102and the distraction head frame 230 can be formed integral to each other.

Further, the distraction head frame 230, the shaft 102 and the firstwing 104 can be formed as one unit. Still further in an embodiment witha screw thread 234 formed at one end of the shaft 102, which thread 234is received in a threaded bore of the first wing 102, the thread 234 canbe laser welded into the threaded bore of the first wing 102, ifdesired.

The distraction head frame 230 is formed to take on a relatively lowprofile because, as described above, it is typically formed ofradiopaque material. As shown in FIG. 2 a, distraction head frame 230has two pairs of parallel sides. The first pair of parallel sides210,212 extends into a pair of flanges 232,233 that define a recess 236.The second pair of parallel sides 214,216 are perpendicular to the firstpair of parallel sides. One of the second pair of parallel sides 214abuts the shaft 102. As will be appreciated by those of skill in theart, neither the first or second pair of parallel sides need be parallelto each other, nor do the first pair of parallel sides need to beperpendicular to the second pair of parallel sides in order to practicethe invention.

With respect to the frame 200 in FIG. 2 a, the distraction head frame230 has an upper surface 218 within the recess 236 with a threaded bore112 therein. The threaded bore 112 receives, for example, a bolt 130 tosecure the second wing 132 to the distraction guide 110 via the tongue136 on the second wing 132 (shown in more detail with respect to FIG. 1a). The profile of the bolt 130 is such that the height of the bolt 130and the tongue 136 fits within the recess 236.

The lower surface 220 opposing the upper surface 218 can have a firstportion 222 that is parallel, or substantially parallel, to the uppersurface 218.

Additionally, a second portion 224 can be angled from the first portion222 toward one of the second parallel sides 216. The angledconfiguration of the lower surface 220 is designed to facilitate theangled profile of the distraction guide.

FIG. 2 b shows a perspective view of the distraction guide 110. Theframe 200, as described above, is manufactured from radiopaque material.A cap 260 is formed of radiolucent material, such as a suitable polymer,around the frame 200.

Suitable polymers include, but are not limited to the polyketonesdiscussed above with respect to the spacer configurations. Accordingly,for example, PEEK, PEKK, PEK, PEKEKK and PEEKK can be used as well asthe other materials that are suitable for the spacer 150. As will beappreciated by those of skill in the art, the cap 260 can be associatedwith the frame 200 by a variety of techniques such that the cap 260 isformed to the frame 200 or is adhered to the frame 200 using a suitablemethod. As illustrated in FIG. 2 b, the cap 260 has a higher profilethan the frame 200 and is shaped to facilitate the second end 204 of thedistraction guide 110 acting to expand tissue when the distraction guideis implanted between spinous processes or used to distract adjacentspinous processes.

Referring now to FIGS. 3 a-6 b, various embodiments of spacers aredepicted.

In FIGS. 3 a, 3 b and 3 c, the spacer 350 includes an outer spacer 352and an inner spacer 354. Inner spacer 354 has a bore 360 therethroughthat enables the spacer 350 to rotate about the shaft 102 of implant 100shown in FIG. 1 a.

Each of the inner and outer spacers of the spacer 350 can have across-section that is elliptical, oval, ovoid, football-shaped,circular-shaped, rectangular with rounded ends (where the cross-sectionhas two somewhat flattened surfaces and two rounded surfaces similar tothe effect of a flattened ellipse). Further, the inner spacer and outerspacer can have different cross-sectional shapes relative to each other.At least the minor outer diameter of the outer spacer is between 6 mmand 14 mm. Typically, the minor outer dimension is one of 6 mm, 8 mm, 10mm, 12 mm, and 14 mm. The different sizes enable the spacer toaccommodate different sized patients.

As depicted in FIG. 3 a, the spacer 350 is a rectangle with rounded endsor a flattened ellipse, as it has two sides that are almost parallel toeach other, and the ends connecting the parallel sides are curved,similar to a “race-track.” Thus, in this and other embodiments, the twosides or surfaces of the spacer, including the upper and the lowerspacer, can also be flattened or slightly radiused. The bore 360 islocated in the center of the inner spacer 354 and there is a gap 362between the upper and lower portions of the outer spacer 352 and theinner spacer 354. A gap 370 is provided between the inner and outerspacers at the rounded ends 356,358. In a preferred embodiment, forabout an 8 millimeter spacer 350, the upper and lower gaps 362 are about0.012 of an inch or about a quarter of a millimeter each for a totalcombined gap of about one half of a millimeter. The gaps 370 at thecurved ends 356,358 are about 0.002 of an inch or slightly less than atenth of a millimeter each in a preferred embodiment. The gap 370 forall of the other spacers is preferably, as specified above, for the 8 mmspacer. For the 6 millimeter spacer, generally this is made of one piecesuch as seen in FIG. 1 f.

However, for the other spacers, these spacers are preferably made of twopieces as seen for example in FIG. 3 a. The table below sets ourpreferred dimensions for the combined upper and lower gap dimension forthe spacers.

Spacer Minor Dimension Total Combined Gap Dimension  6 mm n/a  8 mm0.020 in (0.51 mm) 10 mm 0.025 in (0.64 mm) 12 mm 0.030 in (0.76 mm) 14mm 0.035 in (0.89 mm)

The gap 362 closed and the inner and outer spacers touch each other whenthe spacer is loaded with 800 Newtons of force. The design is made totake repeated loading at 1200 Newtons of force.

In the above embodiment, the outer spacer 352 is movably or slidablymounted on the inner spacer 354, and the inner spacer 354 is rotatablymounted on the shaft 102 of the implant 100.

As discussed above, the spacer, including either the inner spacer orouter spacer, or both, can be made of deflectable and flexible material.As discussed above, suitable material is a polymer such as for examplepolyetheretherketone (PEEK). Other suitable materials can include thosedescribed above. Further, titanium can be used.

Further, the deflectable or flexible material can have a graduatedstiffness to help gradually distribute the load when the spinousprocesses place a force upon the exterior surface of the outer spacer352. This can be accomplished by forming multiple layers of thedeflectable or flexible material with decreasing stiffness or hardnessfrom the center of the spacer 350 outwardly. Alternatively, the materialcan have a higher stiffness or hardness in the center of the innerspacer.

Persons of skill in the art will appreciate that the embodiments shownin FIGS. 4 a-6 b, can be made of the materials similar to thoseemphasized in the embodiment shown in FIGS. 1 a and 3 a.

Now referring to FIGS. 4 a and 4 b, again the spacer 450 is depicted asa somewhat flattened ellipse with rounded ends 456,458, where two sidesare somewhat parallel to each other and the ends connecting the parallelsides are curved, similar to a “race-track.” The bore 460 is locatedoff-center within the inner spacer 454. Further, there are gaps 462,470between the outer spacer 452 and the inner spacer 454. Except for thelocation of the bore 460, the dimensions and materials of the embodimentof FIGS. 4 a and 4 b are similar to that of FIG. 3 a and FIG. 3 b.

The off-center bore 460 allows a greater portion of the spacer 450 to bepositioned close to the vertebral bodies. With an ovoid (“egg-shaped”)spacer, off-set the bore 460 is preferably close to the bulbous end ofthe spacer with the more pointed end directed toward the vertebralbodies in order to attain the advantages of the spacer being closer tothe vertebral bodies and enhanced distributed load bearing.

Turning now to FIG. 5, the spacer 550 is depicted as having a circularcross-section. The bore 560 is located within the inner spacer 554.Further, there are gaps 562,570 between the outer spacer 552 and theinner spacer 554. The dimensions of the gap would be the same as thosediscussed with respect to the embodiment shown in FIG. 3 a. Theembodiment of FIG. 3 a can have a diameter that is the minor diameter ofthe embodiments shown in FIGS. 1 a, 3 a, and 4 a.

Also, as will be appreciated by those in skill in the art, the outerspacer 552 can be movably mounted on the inner spacer 554 and the innerspacer 554 can be rotatably mounted on the shaft 102 of the implant 100or any other suitable implant.

In FIGS. 6 a and 6 b, the spacer 650 is depicted as having an outerspacer 652 and an inner spacer 654 of two different cross-sectionalshapes. In this embodiment, the outer spacer 652 is elliptical and theinner spacer is football-shaped in cross-sections. The bore 660 islocated off-center within the inner spacer 654. However, as will beappreciated by those of skill in the art, the bore 660 can be locatedcentrally within the inner spacer without departing from the scope ofthe invention.

The gaps 662 between the outer spacer 652 and the inner spacer 654 arecrescent-shaped as a result of the inner and outer spacers havingdifferent cross-sectional shapes. Thus, the gap can have a width rangingfrom approximately between 0.25 mm at the minor diameter (greatestvertical height) to just enough space at the apexes 662,664 of the innerspacer 654 so that the outer spacer can slide over the inner spacer. Theinner spacer 654 can be rotatably mounted on the shaft 102 of theimplant 100.

The embodiment of this implant as well as the several other implantsdescribed herein act to limit extension (backward bending) of the spine.These implants, however, do not inhibit the flexion (forward bending) ofthe spinal column.

The foregoing description of embodiments of the present invention hasbeen provided for the purposes of illustration and description. It isnot intended to be exhaustive or to limit the invention to the preciseforms disclosed. Many modifications and variations will be apparent tothe practitioner skilled in the art.

The embodiments were chosen and described in order to best explain theprinciples of the invention and its practical application, therebyenabling others skilled in the art to understand the invention and thevarious embodiments and with various modifications that are suited tothe particular use contemplated. It is intended that the scope of theinvention be defined by the following claims and its equivalence.

Interspinous Implants

FIGS. 7 and 8 illustrate an implant 700 in accordance with an embodimentof the present invention. The implant 700 comprises a wing 730, a spacer720, and a lead-in tissue expander (also referred to herein as adistraction guide) 710. The distraction guide 710 in this particularembodiment is wedge-shaped, i.e., the implant has an expandingcross-section from a proximal end of the implant 740 to a region 750where the guide 710 joins with the spacer 720 (referencing for thefigures is based on the point of insertion of the implant betweenspinous processes). As such, the distraction guide functions to initiatedistraction of the soft tissue and the spinous processes when theimplant 700 is surgically inserted between the spinous processes. It isto be understood that the distraction guide can be pointed and the like,in order to facilitate insertion of the implant between the spinousprocesses of adjacent cervical vertebrae. It is advantageous that theinsertion technique disturb as little of the bone and surrounding tissueor ligaments as possible in order to reduce trauma to the site andpromote early healing, and prevent destabilization of the normalanatomy. In the embodiment of FIGS. 7 and 8, there is no requirement toremove any of the bone of the spinous processes and no requirement tosever, or remove from the body, ligaments and tissues immediatelyassociated with the spinous processes. For example, it is unnecessary tosever the ligamentum nuchae, (supraspinous ligament) which partiallycushions the spinous processes of the upper cervical vertebrae.

As can be seen in FIGS. 7-9, the spacer 720 can be teardrop-shaped incross-section perpendicular to a longitudinal axis 725 of the implant.In this way, the shape of the spacer 720 can roughly conform to awedge-shaped space, or a portion of the space, between adjacent spinousprocesses within which the implant 700 is to be positioned. In otherembodiments, the spacer 720, can have alternative shapes such ascircular, wedge, oval, ovoid, football-shaped, and rectangular-shapedwith rounded corners and other shapes, and be within the spirit andscope of the invention. The shape of the spacer can be selected for aparticular patient so that the physician can position the implant asclose as possible to the anterior portion of the surface of the spinousprocess. The shape selected for the spacer 720 can effect the contactsurface area of the implant 700 and the spinous processes that are to besubject to distraction. Increasing the contact surface area between theimplant and the spinous processes can distribute the force and loadbetween the spinous frame and the implant.

As can be seen in FIGS. 7 and 8, the wing 730 in this embodiment 700 iselliptically-shaped in cross-section perpendicular to a longitudinalaxis 725 of the spacer 720 and distraction guide 710. The dimensions ofthe wing 730 can be larger than that of the spacer 720, particularlyalong the axis of the spine, and can limit or block lateral displacementof the implant in the direction of insertion along the longitudinal axis725. As illustrated in the embodiment of FIG. 9, the wing 730 can haveother cross-sectional shapes, such as teardrop, wedge, circular, oval,ovoid, football-shaped, and rectangular-shaped with rounded corners andother shapes, and be within the spirit and scope of the invention. Thewing 730 has an anterior portion 733 and a posterior portion 735.

In other embodiments, the implant 700 can have two wings, with a secondwing 760 (shown in FIG. 10) separate from the distraction guide 710,spacer 720 and first wing 730. The second wing can be connected to theproximal end of the spacer 720. The second wing 760, similar to thefirst wing 730, can limit or block lateral displacement of the implant700, however displacement is limited or blocked in the direction alongthe longitudinal axis 725 opposite insertion. When both the first wing730 and second wing 760 are connected with the implant and the implantis positioned between adjacent spinous processes, a portion of thespinous processes can be sandwiched between the first and second wing,limiting any displacement along the longitudinal axis 725.

As can be seen in FIG. 10, the second wing 760 can be teardrop-shaped incross-section. The wider section or end 762 of the teardrop shape is theposterior end of the second wing 760 and the narrower section or end 769is the anterior end of the second wing 760. Unlike the first wing 730,however, the sides of the second wing 760 define a space 770 with a lip780 that allows the second wing 760 to pass over the distraction guide710 to meet and connect with the spacer 720. The second wing 760 is thensecured to the spacer 720 toward the end of the spacer located distallyfrom the first wing 740. The second wing 760 is connected with theimplant after the implant 700 is positioned between the spinousprocesses.

It is to be understood that the implant can be made in two pieces. Thefirst piece can include the first wing 730, the spacer 720, and thedistraction guide 710. The second piece can include the second wing 760.Each piece can be manufactured using technique known in the art (e.g.,machining, molding, extrusion). Each piece, as will be more fullydiscussed below, can be made of a material that is bio-compatible withthe body of the patient. For example the implants can be made ofstainless steel and titanium. Additionally, a shape memory metal such asNitinol, which is a combination of titanium and nickel, can also beused. Further polymers can also be used. The implant can be formed withmultiple pieces and with the pieces appropriately joined together, oralternatively, the implant can be formed as one piece or joined togetheras one piece.

Further embodiments of implants in accordance with the present inventionare depicted in FIGS. 11-13. In such embodiments, the spacer 810 can berotatable about the longitudinal axis 840 relative to the first wing730, or relative to a first and second wing 730,760 where two wings areused. The spacer 810 can be rotatable or fixed relative to thedistraction guide 710. Where the spacer 810 is rotatable, the spacer 810can include a bore 820 running the length of the longitudinal axis 840,and a shaft 830 inserted through the bore 820 and connecting thedistraction guide 710 with the first wing 730. It can be advantageous toposition any of the implants taught herein as close as possible to thevertebral bodies. The rotatable spacer 810 can rotate to conform to orsettle between the bone structures of the cervical spine as the implantis inserted between the spinous processes, so that on average thecontact surface area between the spacer 810 and both of the spinousprocesses can be increased over the contact surface area between a fixedspacer 810 and the spinous processes. Thus, the rotatable spacer 810improves the positioning of the spacer independent of the wings relativeto the spinous processes. The embodiment of FIG. 12 has a first wing 730and if desired, a second wing 760 similar to the wing depicted in theembodiment of FIG. 9. As discussed below, the shape of the wings inFIGS. 9 and 12 is such that the implants accommodate the twisting of thecervical spine along its axis as, for example, the head of a patientturning from side to side.

FIG. 14 is a perspective view and FIG. 15A is an end view of stillanother embodiment of an implant in accordance with the presentinvention, wherein the posterior portion 735 of the teardrop-shapedfirst wing 730 is truncated 910, making the first wing 730 more ovoid inshape. In this configuration, the anterior portion 733 of the first wing730 can be longer than the truncated posterior end 910 of the first wing730. As in previous embodiments, the spacer 810 of such implants 900 canbe a rotatable spacer rather than a fixed spacer. FIG. 15B illustrates asecond wing for use with such implant 900 having a truncated posteriorend 940. Truncation of the posterior ends 910,940 of the first andsecond wings 730,760 can reduce the possibility of interference ofimplants 900 having such first and second wings 730,760 positionedbetween spinous processes of adjacent pairs of cervical vertebrae, e.g.,implants between cervical vertebrae five and six, and between six andseven.

During rotation of the neck, the spinous process move past each other ina scissor-like motion. Each cervical vertebra can rotate relative to thenext adjacent cervical vertebra in the general range of about 6°-12°. Inaddition, about 50 percent of the rotational movement of the neck isaccomplished by the top two neck vertebrae. Thus, such embodiments canaccommodate neck rotation without adjacent embodiments interfering witheach other.

With respect to the prior embodiments which have first and second wings,the second wing 760, can be designed to be interference-fit onto thespacer 720 (where the spacer is fixed) or a portion of the distractionguide 710 adjacent to the spacer 720 (where the spacer is rotatable).Where the second wing 760 is interference-fit, there is no additionalattachment device to fasten the second wing 760 relative to theremainder of the implant.

Alternatively, various fasteners can be used to secure the second wing760 relative to the remainder of the implant. For example, FIGS. 16-17illustrate an embodiment of an implant 1000 including a teardrop-shapedsecond wing 1010 having a bore 1020 through a tongue 1030 at theposterior end of the second wing 760. The bore on the second wing 1020is brought into alignment with a corresponding bore 1040 on the spacer720 when the second wing 760 is brought into position by surgicalinsertion relative to the rest of the implant. A threaded screw 1050 canbe inserted through the aligned bores in a posterior-anterior directionto secure the second wing 760 to the spacer 720. The direction ofinsertion from a posterior to an anterior direction has the screwengaging the bores and the rest of the implant along a direction that isgenerally perpendicular to the longitudinal axis 725. This orientationis most convenient when the surgeon is required to use a screw 1050 tosecure the second wing 760 to the rest of the implant. Other securingmechanisms using a member inserted into corresponding bores 1020,1040 onthe spacer 720 and second wing 760 are within the spirit of theinvention.

It should be understood that a rotatable spacer 810 also can beaccommodated by this embodiment. With a rotatable spacer 810, the secondwing 760 would be attached to a portion of the distraction guide 710that is located adjacent to the rotatable spacer 810.

FIGS. 19A-20B depict a further embodiment 1100 wherein the second wing760 is secured to the spacer 720 by a mechanism including a flexiblehinge 1115, with a protrusion 1130 on the end of the hinge 1110 adjacentto the lip 780 of the hole 770 defined by portions of the second wing760. The securing mechanism also encompasses an indentation 1140 on thespacer 720, wherein the indentation accommodates the protrusion 1130 onthe end of the flexible hinge 1115. During surgery, after insertion ofthe distraction guide 710, spacer 720, and first wing 730, the secondwing 760 is received over the distraction guide 710 and the spacer 720.As the second wing 760 is received by the spacer 720, the flexible hinge1115 and its protrusion 1130 deflect until the protrusion 1130 meets andjoins with the indentation 1140 in the spacer 720, securing the secondwing 760 to the spacer 720. Again in embodiments where the spacer canrotate, the indentation 1140 is located on an end of the distractionguide 710 that is adjacent to 750 the rotatable spacer 810. With respectto the flexible hinge 1115, this hinge is in a preferred embodimentformed with the second wing 760 and designed in such a way that it canflex as the hinge 1115 is urged over the distraction guide 710 and thespacer 720 and then allow the protrusion 1130 to be deposited into theindentation 1140.

Alternatively, it can be appreciated that the indentation 1140 can existin the second wing 760 and the flexible hinge 1115 and the protrusion1130 can exist on the spacer 720 in order to mate the second wing 760 tothe spacer 720. Still alternatively, the flexible hinge 1115 can bereplaced with a flexible protrusion that can be flexed into engagementwith the indentation 1140 in the embodiment with the indentation 1140 inthe spacer 720 or in the embodiment with the indentation 1140 in thesecond wing 760.

FIGS. 21A-22 illustrate an embodiment of an implant 1200 whereinanterior ends of a first wing 730 and second wing 760 flare out at anangle away from the spacer 720 and away from each other. The cervicalspinous processes are themselves wedge-shaped when seen from a top view.That the implant 1200 can roughly conform with the wedge shape so thatthe implant 1200 can be positioned as close as possible to the vertebralbodies of the spine where the load of the spine is carried. Thus thefirst 730 and the second wings 760 are positioned relative to thespacer, whether the spacer is fixed 720 or rotatable 810, so that thewings flare out as the wings approach the vertebral body of the spine.FIG. 21B depicts a top view of the implant 1200 of FIG. 21A. As isevident from FIG. 21B, the first wing 730 is aligned at an angle withrespect to a line perpendicular to the longitudinal axis. In oneembodiment, the angle is about 30°, however, the angle Θ can range fromabout 15° to about 45°. In other embodiments, other angles of the firstwing 730 relative to the spacer 720 outside of this range arecontemplated and in accordance with the invention. Likewise, the secondwing 760 can be aligned along a similar, but oppositely varying range ofangles relative to the line perpendicular to the longitudinal axis. Thefirst and second wing 730,760 thus form an obtuse angle with respect tothe spacer 720 in this embodiment. The second wing 760 defines an innerhole 770 which is outlined by the lip 780. As is evident, the lip 780can be provided at an angle relative to the rest of the second wing 760so that when the lip 780 is urged into contact with the spacer 720, thesecond wing 760 has the desired angle relative to the spacer 720. Asdiscussed above, there are various ways that the second wing 760 issecured to the spacer 720. FIG. 21A depicts a top view of one suchimplant 1200 placed between the spinous processes of adjacent cervicalvertebrae. FIG. 22 is a top view illustrating two layers of distractingimplants 1200 with flared wings.

Systems and methods in accordance with the present invention can includedevices that can be used in cooperation with implants of the presentinvention. FIG. 23 illustrates “stops” (also referred to herein as“keeps”) 1310, which are rings of flexible biocompatible material, whichcan be positioned around the spinous processes of adjacent cervicalvertebrae and located posteriorly to the implant. The keeps 1310 canprevent posterior displacement of the implants. In one embodiment, thekeeps can include a ring 1310 having a slit 1320. The keeps 1310 can besomewhat sprung apart, so that the keep 1310 can be fit over the end ofthe spinous process and then allowed to spring back together in order tohold a position on the spinous process. The keep 1310 can act as a blockto the spacer 720 in order to prevent the implant from movement in aposterior direction.

Distractible Interspinous Implants

In still other embodiments, implants in accordance with the presentinvention can be distractible in situ. FIG. 24 is a perspective view ofone such implant. The implant 1800 comprises a body 1801 adapted to beinserted between the spinous processes, and a distracting insert 1806.The body 1801 can include two substantially mirror parts: a first part1802 adapted to contact and support an upper spinous process and asecond part 1804 adapted to contact and support a lower spinous process.When positioned such that the first and second parts 1802,1804 alignwith and abut one another, the body 1801 can resemble implants describedabove in reference to FIGS. 7-23. In other embodiments, the body 1801can have a shape other than those shown in FIGS. 7-23. Further, in someembodiments the first part 1802 and second part 1804 can have differentshapes, such that when the first part 1802 and second part 1804 alignwith and abut one another, the body 1801 is nonsymmetrical about theplane of contact. For example, as shown in FIG. 25A, the first part 1802can have a saddle-like, or concave shape conforming roughly with a shapeof a contact surface of the second cervical, while the second part 1804has a substantially convex shape.

The body 1801 can include a wing 1830 having a first and second portion1832,1834, a spacer 1820 having a first and second portion 1822,1824,and a lead-in tissue expander (also referred to herein as a distractionguide) 1810 having a first and second portion 1812,1814. The distractionguide 1810 as shown is wedge-shaped, i.e., the distraction guide 1810has an expanding cross-section from the proximal end of the body 1801 toa region where the distraction guide 1810 joins with the spacer 1820. Assuch, the distraction guide 1810 functions to initiate distraction ofthe soft tissue and the spinous processes when the body 1801 issurgically inserted between the spinous processes.

The spacer 1820, as shown, is teardrop-shaped in a cross-sectionperpendicular to the spacer's longitudinal axis 1825. The spacer 1820can be shaped to roughly conform to a wedge-like space, or a portion ofthe space, between adjacent spinous processes, for example as betweenthe spinous processes of the fourth and fifth cervical vertebrae. Theshape of the spacer 1820 can be selected for a particular patient,and/or a particular pair of adjacent spinous processes, and can varysubstantially. Thus, in other embodiments, the spacer 1820 can haveother cross-sectional shapes, such as circular, wedge, oval, ovoid,football-shaped, and rectangular-shaped with rounded corners and othercross-sectional shapes and/or can be custom fabricated for theparticular patient and the anatomy of the particular spinal processesbetween which the implant 1800 is to be placed.

In still other embodiments, the spacer 1820 can have a nonsymmetricalcross-sectional shape, for example where a space between adjacentspinous processes is nonsymmetrical.

The ability to select a size and shape of the spacer 1820 to suit apatient allows the physician to choose an implant 1800 that can beplaced closer to the vertebral bodies than farther away for additionalsupport. The shape selected for the spacer 1820 can define the contactsurface area between the implant 1800 and the spinous processes that aresubject to distraction.

Increasing the contact surface area between the implant 1800 and thespinous processes distributes the force and load between the spinousframe and the implant 1800. Generally, a teardrop or wedge-shaped spacer1820 can allow for more load-bearing contact between the spacer 1820 andthe spinous processes of the cervical vertebrae, and embodiments havingsuch shapes will be more particularly described.

As shown, the wing 1830 can be tear-drop shaped in cross-section,although having a minor dimension that is larger than that of the spacer1820, and can limit or block lateral displacement of the implant 1800 inthe direction of insertion along the longitudinal axis 1825. However,the wing 1830 need not be teardrop shaped. In other embodiments, thewing 1830 can have some other shape, for example the wing 1830 can beelliptical, wedge, circular, oval, ovoid, football-shaped, andrectangular-shaped with rounded corners and other shapes, and be withinthe spirit and scope of the invention. Further, as with the spacer 1820,the wing 1830 can have a nonsymmetrical cross-sectional shape. The shapeof the wing 1830 can be chosen to most easily fit into place whileavoiding obstructions, such as soft tissue or bone, or other implants,while still blocking or limiting lateral displacement.

The wing 1830 can include one or more cavities 1852,1854 that extendthrough the wing 1830 and through at least a portion of the spacer 1820.The one or more cavities 1852,1854 should comprise a first groove formedin the first part 1802 and a second groove formed in the second part1804, so that the cross-section of the cavity 1852,1854 can be expandedduring insertion of a distracting insert 1806, as described below. Thebody 1801 of FIG. 24 includes a first cavity 1852 and a second cavity1854 to receive a first insert 1842 and a second insert 1844 of thedistracting insert 1806. Having two or more cavities and correspondinginserts can prevent relative rotation between the body 1801 and thedistracting insert 1806. In the embodiment shown in cross-section inFIG. 25B, each cavity has a substantially circular cross-section, and issized roughly in proportion to the width of the spacer 1820, so that thefirst cavity 1852 is larger in diameter than the second cavity 1854.

However, in other embodiments, the cavities need not be shaped as shown.For example, the cavities can be elliptical, dual-lobed, or otherwiseshaped. Further, the cavities need not be sized as shown. For example,the cavities can be roughly the same size. As shown in FIG. 25C, instill further embodiments, the body 1801 can include more than twocavities 1852,1854, 1856, and each cavity can have similar, or differentshape. As shown in FIG. 25D, in still other embodiments the body 1801can include a single cavity 1852, such as a wedge-shaped cavity roughlycorresponding to a shape of the spacer 1820. Myriad different cavityshapes and cavity configurations can be employed to achieve separationof a body 1801 positioned between spinous processes. However, it can bepreferable that the shape of the cavities 1852,1854, 1856 shouldcorrespond roughly with the shape of the upper and lower surfaces of theinserts 1842,1844, 1846 of the distracting insert 1806, so that, asshown in FIG. 25B-25D, a load applied to the body 1801 can bedistributed relatively evenly over the surface of the cavities1852,1854, 1856.

Once the body 1801 is positioned between adjacent spinous processes, thefirst and second parts 1802,1804 of the body 1801 can be separated,thereby expanding the width of the body 1801 and distracting theadjacent spinous processes. In one embodiment, separation of the firstand second parts 1802,1804 can be accomplished, for example, bypositioning the distracting insert 806 within the body 1801 such thatthe first and second parts 1802,1804 are urged apart. As mentionedabove, the distracting insert 1806 can include one or more insertsassociated with the one or more cavities, the one or more inserts beingfixedly connected to a cap 1808. As shown in FIG. 24, the distractinginsert 1806 includes a first insert 1842 and a second insert 1844, eachof the inserts being fixedly connected with a cap 1808 having a shaperoughly corresponding to a shape of the wing 1830. Inserts 1842,1844have distracting tips that can initially urge the halves of the implant1800 apart. In other words, the inserts 1842,1844 have tips withever-increasing cross-section so that the tips can be easily inserted inthe cavities 1852,1854 and the continual movement of the insert1842,1844 urges the halves of the body 1801 apart. Thus, the tips of theinsert 1842,1844 can be smaller than the cavities 1852,1854 in order tofacilitate initial insertion into the cavities 1852,1854. As shown inFIGS. 25B-D, the one or more inserts 1842,1844, 1846 can be sized suchthat they have a height larger than a diameter (or height) of the one ormore cavities 1852,1854, 1856, so that when positioning the insertswithin the cavities, the first part 1802 and second part 1804 of thebody 1801 are separated by the difference in height of the inserts andthe diameter (or height) of the cavities (i.e., an additionaldistraction height).

As shown in FIG. 26A, the body 1801 can be inserted between adjacentspinous processes by piercing and/or displacing the soft tissue (i.e.,the interspinous ligament) with the distraction guide 1810 andstretching and/or displacing the tissue so that the spacer 1820 fitsbetween the spinous processes. The height of the first part 1802 andsecond part 1804 of the body 1801 can be minimized by abutting the firstpart 1802 and the second part 1804 so that the body 1801 can bepositioned between the spinous processes.

As described above, and as can be seen in FIG. 26A, the shape of thebody 1801 can resemble the shape of a space between adjacent spinousprocesses. With the body 1801 in place, the distracting insert 1806 canbe inserted into the body 1801, causing the first part 1802 and secondpart 1804 to separate, as described above and shown in FIG. 26B. Asdiscussed above, proximal ends of the inserts 1842, 1844 of thedistracting insert 1806 can be tapered to assist in guiding the inserts1842,1844 into the cavities 1852,1854, and to ease separation of thefirst and second parts 1802,1804. The distracting insert 1806 can haveinserts 1842,1844 sized to achieve a desired amount of distraction ofthe spinous processes.

As with the body 1801, multiple distracting inserts 1806 can be madeavailable to a physician, the physician choosing a distracting insert1806 sized to suit a particular patient. A system in accordance with oneembodiment of the present invention can comprise a plurality of bodies1801, each body 1801 having different shape and/or height.

Such a system can further comprise a plurality of distracting inserts1806, having inserts corresponding to cavities of the bodies 1801, andhaving different heights to achieve different amounts of distraction.Methods in accordance with embodiments of the present invention canapply such systems so that a physician can select implant componentsappropriate to the patient at the time of surgery, and can furthersubstitute different bodies and/or different distracting inserts basedon evaluation or reevaluation during surgery.

FIG. 27A is a cross-sectional side view of a distractible implant 1800in accordance with one embodiment of the present invention positionedbetween adjacent spinous processes, and having an insert 1842 of thedistracting insert 1806 partially inserted within a cavity 1852 of thebody 1801. As described above, when inserted between spinous processes,the first part 1802 of the body 1801 is aligned and abutted with thesecond part 1804 of the body 1801. The first part 1802 and second part1804 should remain aligned while the body 1801 is inserted between thespinous processes, and further should remain aligned while thedistracting insert 1806 is mated with the body 1801. In order tomaintain proper alignment, one of the first and second parts 1802,1804can include alignment pins (or protrusions) 2118 that mate withcorresponding holes 2119 of the other of the first and second parts1802,1804. The pins 2118 can be made of the same or different materialas the body 1801, and can be integrally formed or mated with thecorresponding part. For example, where the pins 2118 are made oftitanium, and the body 1801 is made of a biocompatible thermoplastic,the pins 2118 can be press fit into the second part 1804. The pins 2118are free to slide in and out of the holes 2119, but are prevented fromseparating from the holes 2119 by pressure of the spinous processes. Asan insert 1842 enters a cavity 1852 of the body 1801, the distal end ofthe body 1801 begins to separate, as shown. As the spinous processes aredistracted, the pins 2118 move within the holes 2119, allowingseparation of the first part 1802 and second part 1804. The pins 2118prevent relative shifting or sliding along the longitudinal axis oralong the length of the spinous process. The pins 2118 (andcorresponding holes 2119) preferably have a height larger than themaximum distraction height, thereby preventing the pins 2118 fromseparating from the holes 2119 and allowing relative shifting of thefirst and second parts 1802,1804. FIG. 27B is a top view showing theposition of the pins 2118 relative to a first and second cavity1852,1854. Two pins 2118 are shown extending through holes 2119 of thesecond part 1802, however, in other embodiments, any number of pins 2118or protrusions can be integrally formed or connected with one of thefirst and second parts 1802,1804.

In an alternative embodiment (not shown), the first part 1802 and secondpart 1804 of the body 1801 can be bound together by a flexible,artificial ligament or suture material. For example, the material can bea bio-compatible polymer having flexible properties. The artificialligament or suture material can limit the shifting between the firstpart 1802 and second part 1804. In still other embodiments, some otherdevice can be employed to maintain alignment of the first and secondparts 1802,1804. It is intended that in some embodiments of the presentinvention, it is preferable to maintain alignment of the first andsecond parts 1802,1804 during distraction. As one of ordinary skill inthe art can appreciate, many different devices can be employed tomaintain alignment between the first and second parts 1802,1804 of thebody 1801.

As shown in FIGS. 28A and 28B, the distracting insert 1806 can besecured to the body 1801 by a clip 2260. The body 1801 as shown in FIGS.28A-28D is the same as the body 1801 of FIG. 24. Commonly labeledcomponents are as described above. However, it should be noted thatother embodiments of a body 1801 can be used with distracting inserts1806 described with reference to FIG. 28A-28D. In one embodiment, theclip 2260 can include a first tab 2262 and a second tab 2264. Each tab2262,2264 can extend across at least a portion of the width of therespective portion of the wing 1830 along the longitudinal axis 1825.When the distracting insert 1806 is mated with the body 1801, the wing1830 can be interference-fit with the distracting insert 1806 so thatthe wing 1830 is held between the tabs 2262,2264. The pressure appliedto the surfaces of the wing 1830 should create sufficient frictionalforce to prevent relative movement between the body 1801 and distractinginsert 1806. In other embodiments, the clip 2260 can comprise a singlelip along a portion of, or the entire periphery of the cap (and wing1830) and can extend across at least a portion of the width of the wing1830 along the longitudinal axis 1825.

As shown in FIG. 28C, in still other embodiments, each tab 2262,2264 caninclude a protrusion 2263,2265 located at a proximal end of the tab2262,2264. The wing 1830 can include indentations 2273,2275, orcavities, for receiving each of the protrusions 2263,2265 so that whenthe protrusions are positioned within the respective indentations, theclip 2260 is locked in place. Alternatively, the tab 2262,2264 canextend beyond a ledged wing 1830, so that the clip 2260 can be locked inplace when the protrusions 2263,2265 clear the wing 1830. As describedabove, the distracting insert 1806 is mated with the positioned body1801 by gradually urging the inserts of the distracting insert 1806along the length of the cavities of the spacer 1820. The protrusions2263,2265 can be beveled, so that as the protrusions contact an outerlip of the wing 1830, the tabs 2262,2264 deflect upward, allowing thedistracting insert 1806 to continue moving into position along thelongitudinal axis. When the protrusions 2263,2265 find the indentations2273,2275 of the wing 1830 (or alternatively, when the protrusions clearthe ledge), the clasp 2260 locks into place and the distracting insert1806 is mated with the body 1801.

In still further embodiments, the distracting insert 1806 need notinclude a clip, but can be mated with the body 1801 using some otherdevice. For example, as shown in FIG. 28D, an insert 1842 can includeone or more pegs 2272,2274, and one or more corresponding through-holes2282,2284 (or cavities) within the first wing 1830. The one or more pegs2272,2274 can be sized such that a feature of the one or more pegs2272,2274 is approximately the same width, or slightly larger than awidth, w, of the one or more corresponding through-holes 2282,2284, sothat an interference fit is created between the distracting insert 1806and the body 1801, holding the distracting insert 1806 seated in place,and limiting the relative movement of the first part 1802 and secondpart 1804.

Referring to FIG. 29, the implant 1800 can further include a second wing2360, similar to previously described embodiments. The second wing 2360can be connected to the proximal end of the spacer 1820 so that portionsof the adjacent spinous processes are sandwiched between the second wing2360 and the first wing 1830. The second wing 2360, like the first wing1830, can prevent lateral displacement of the body 1801 relative to thespinous processes. The second wing 2360 can be teardrop-shaped and sizedto approximate the shape and size of the first wing 1830 when thedistracting insert 1806 is mated with the body 1801. Likewise, the sidesof the second wing 2360 define a space 2370 with a lip 2380 that allowsthe second wing 2360 to pass over the distraction guide 1810 to meet andconnect with the spacer 1820. The space 2370 defined within the secondwing 2360 should correspond with the distracted height of the body 1801.As described above, systems and methods in accordance with the presentinvention can comprise a plurality of bodies 1801 and a plurality ofdistracting inserts 1806 to suit a particular patient. Likewise, systemsand methods in accordance with the present invention can furthercomprise a plurality of second wings 2360 corresponding in size andshape to the plurality of bodies 1801 and the plurality of distractinginserts 1806. The second wing 2360 can be secured to the spacer 1820,for example as described above. The second wing 2360 is implanted oncethe distraction guide 1810, spacer 1820, and first wing 1830 areinserted as a unit between the spinous processes of adjacent cervicalvertebrae.

It is to be understood that the various features of the variousembodiments can be combined with other embodiments of the invention andbe within the spirit and scope of the invention. Thus, for example only,the embodiment of FIG. 24 can have truncated wings as depicted in otherembodiments.

Materials for Use in Implants of the Present Invention

It is to be understood that implants in accordance with the presentinvention, and/or portions thereof can be fabricated from somewhatflexible and/or deflectable material.

In these embodiments, the implant and/or portions thereof can be madeout of a polymer, such as a thermoplastic. For example, in oneembodiment, the implant can be made from polyketone, known aspolyetheretherketone (PEEK). Still more specifically, the implant can bemade from PEEK 450G, which is an unfilled PEEK approved for medicalimplantation available from Victrex of Lancashire, Great Britain. Othersources of this material include Gharda located in Panoli, India. PEEKhas the following approximate properties:

Property Value Density 1.3 g/cc Rockwell M 99 Rockwell R 126 TensileStrength 97 MPa Modulus of Elasticity 3.5 GPa Flexural Modulus 4.1 GPa

The material specified has appropriate physical and mechanicalproperties and is suitable for carrying and spreading a physical loadbetween the adjacent spinous processes. The implant and/or portionsthereof can be formed by extrusion, injection, compression moldingand/or machining techniques.

In some embodiments, the implant can comprise, at least in part,titanium or stainless steel, or other suitable implant material which isradiopaque, and at least in part a radiolucent material that does notshow up under x-ray or other type of imaging. For example, in oneembodiment, a first wing, a second wing and a shaft can comprise aradiopaque material (e.g., titanium) and a rotatable spacer and alead-in tissue expander can comprise a radiolucent material (e.g.,PEEK). In such an embodiment, under imaging the implant looks like an“H”. The physician can have a less obstructed view of the spine underimaging, than with an implant comprising radiopaque materials entirely.However, the implant need not comprise any radiolucent materials.

It should be noted that the material selected can also be filled. Forexample, other grades of PEEK are also available and contemplated, suchas 30% glass-filled or 30% carbon-filled, provided such materials arecleared for use in implantable devices by the FDA, or other regulatorybody. Glass-filled PEEK reduces the expansion rate and increases theflexural modulus of PEEK relative to that which is unfilled. Theresulting product is known to be ideal for improved strength, stiffness,or stability. Carbon-filled PEEK is known to enhance the compressivestrength and stiffness of PEEK and lower its expansion rate.Carbon-filled PEEK offers wear resistance and load carrying capability.

In this embodiment, as described above, the implant is manufactured fromPEEK, available from Victrex. As will be appreciated, other suitablesimilarly biocompatible thermoplastic or thermoplastic polycondensatematerials that resist fatigue, have good memory, are flexible, and/ordeflectable, have very low moisture absorption, and good wear and/orabrasion resistance, can be used without departing from the scope of theinvention.

The spacer can also be comprised of polyetherketoneketone (PEKK). Othermaterial that can be used include polyetherketone (PEK),polyetherketoneetherketoneketone (PEKEKK), andpolyetheretherketoneketone (PEEKK), and generally apolyaryletheretherketone. Further, other polyketones can be used as wellas other thermoplastics. Reference to appropriate polymers that can beused in the implant can be made to the following documents, all of whichare incorporated herein by reference. These documents include: PCTPublication WO 02/02158 A1, dated Jan. 10, 2002, entitled“Bio-Compatible Polymeric Materials;” PCT Publication WO 02/00275 A1,dated Jan. 3, 2002, entitled “Bio-Compatible Polymeric Materials;” and,PCT Publication WO 02/00270 A1, dated Jan. 3, 2002, entitled“Bio-Compatible Polymeric Materials.” Other materials such as Bionate®,polycarbonate urethane, available from the Polymer Technology Group,Berkeley, Calif., may also be appropriate because of the good oxidativestability, biocompatibility, mechanical strength and abrasionresistance. Other thermoplastic materials and other high molecularweight polymers can be used.

Methods for Implanting Interspinous Implants

A minimally invasive surgical method for implanting an implant 100,1800in the cervical spine is disclosed and taught herein. In this method, asshown in FIG. 30, preferably a guide wire 2480 is inserted through aplacement network 2490 into the neck of the implant recipient. The guidewire 2480 is used to locate where the implant is to be placed relativeto the cervical spine, including the spinous processes. Once the guidewire 2480 is positioned with the aid of imaging techniques, an incisionis made on the side of the neck so that an implant in accordance with anembodiment of the present invention, can be positioned in the neckthorough an incision and along a line that is about perpendicular to theguide wire 2480 and directed at the end of the guide wire 2480. In oneembodiment, the implant can be a sized implant 100 (i.e., having a bodythat is not distractible), such as described above in FIGS. 7-23 andincluding a distraction guide 710, a spacer 720, and a first wing 730.The implant 700 is inserted into the neck of the patient. Preferablyduring insertion, the distraction end pierces or separates the tissuewithout severing the tissue.

Once the implant 700 is satisfactorily positioned, a second wing 760 canbe optionally inserted along a line that is generally collinear with theline over which the implant 700 is inserted but from the opposite sideof the neck. The anatomy of the neck is such that it is most convenientand minimally invasive to enter the neck from the side with respect tothe implant 700 and the second wing 760. The second wing 760 is mated tothe implant and in this particular embodiment, the second wing 760 issnapped into engagement with the implant 700. In an alternativeembodiment, the second wing 760 is attached to the implant by the use ofa fastener, for example by a screw 1050. Where a screw is used, thescrew 1050 can be positioned using a screw driving mechanism that isdirected along a posterior to anterior line somewhat parallel to theguide wire 2480. This posterior to anterior line aids the physician inviewing and securing the second wing 160 to the implant.

In other embodiments of methods in accordance with the presentinvention, the implant can be a distractible implant 1800, such asdescribed above in FIGS. 24-29. In such embodiments, as shown in FIG.31, preferably a guide wire 2580 is inserted through a placement network2590 into the neck of the implant recipient (as shown and describedabove). Once the guide wire 2580 is positioned with the aid of imagingtechniques, an incision is made on the side of the neck so that adistractible body 1801 in accordance with an embodiment of the presentinvention, can be positioned in the neck thorough an incision and alonga line that is about perpendicular to the guide wire 880 and directed atthe end of the guide wire. The distractible body 1801 can include adistraction guide 1810, a spacer 1820, and a first wing 1830. The body1801 is inserted into the neck of the patient, between adjacent spinousprocesses. Preferably during insertion, the distraction guide 1810pierces or separates the tissue without severing the tissue, and thebody 1801 is positioned so that the spacer 1820 is between the adjacentspinous processes. A distracting insert 1806 is then positioned withinthe incision and urged into one or more cavities of the body 1801,distracting the spinous processes between which the body is positioned.As the distracting insert 1806 mates with the body 1801, the distractinginsert 1806 locks in place.

Once the distractible implant 1800 is satisfactorily positioned anddistracted, a second wing 2360 can optionally be inserted along a linethat is generally collinear with the line over which the body 1801 isinserted but from the opposite side of the neck. The anatomy of the neckis such that it is most convenient and minimally invasive to enter theneck from the side with respect to the body 1801 and the second wing2360. The second wing 2360 can be mated to the body 1801 through aninterference fit, or alternatively by attaching to the body 1801 by theuse of a fastener, or by some other device, as described above. Forexample, where a screw is employed, the screw can be positioned using ascrew driving mechanism that is directed along a posterior to anteriorline somewhat parallel to the guide wire. This posterior to anteriorline aids the physician in viewing and securing the second wing 2360 tothe body 1801.

The foregoing description of the present invention have been presentedfor purposes of illustration and description. It is not intended to beexhaustive or to limit the invention to the precise forms disclosed.Many modifications and variations will be apparent to practitionersskilled in this art. The embodiments were chosen and described in orderto best explain the principles of the invention and its practicalapplication, thereby enabling others skilled in the art to understandthe invention for various embodiments and with various modifications asare suited to the particular use contemplated. It is intended that thescope of the invention be defined by the following claims and theirequivalents.

FIG. 32 is a perspective view of an implant as described in U.S. Pat.No. 6,695,842 to Zucherman, et al. and U.S. Pat. No. 6,712,819 toZucherman et al., both incorporated herein by reference. The implant3100 has a main body 3101. The main body 3101 includes a spacer 3102, afirst wing 3108, a lead-in tissue expander 3106 (also referred to hereinas a distraction guide) and an alignment track 3103. The main body 3101is inserted between adjacent spinous processes. Preferably, the mainbody 3101 remains (where desired) in place without attachment to thebone or ligaments.

The distraction guide 3106 includes a tip from which the distractionguide 3106 expands, the tip having a diameter sufficiently small suchthat the tip can pierce an opening in an interspinous ligament and/orcan be inserted into a small initial dilated opening. The diameterand/or cross-sectional area of the distraction guide 3106 then graduallyincreases until it is substantially similar to the diameter of the mainbody 3101 and spacer 3102. The tapered front end eases the ability of aphysician to urge the implant 3100 between adjacent spinous processes.When urging the main body 3101 between adjacent spinous processes, thefront end of the distraction guide 3106 distracts the adjacent spinousprocesses and dilates the interspinous ligament so that a space betweenthe adjacent spinous processes is approximately the diameter of thespacer 3102.

The shape of the spacer 3102 is such that for purposes of insertionbetween the spinous processes, the spinous processes need not be alteredor cut away in order to accommodate the spacer 3102. Additionally,associated ligaments need not be cut away and there is little or nodamage to the adjacent or surrounding tissues. As shown in FIG. 32, thespacer 3102 is elliptically shaped in cross-section, and can swivelabout a central body (also referred to herein as a shaft) extending fromthe first wing 3108 so that the spacer 3102 can self-align relative tothe uneven surfaces of the spinous processes. Self-alignment can ensurethat compressive loads are distributed across the surface of the bone.As contemplated in Zucherman '842, the spacer 3102 can have, forexample, a diameter of six millimeters, eight millimeters, tenmillimeters, twelve millimeters and fourteen millimeters. Thesediameters refer to the height by which the spacer distracts andmaintains apart the spinous process. For an elliptically shaped spacer,the selected height (i.e., diameter) is the minor dimension measurementacross the ellipse. The major dimension is transverse to the alignmentof the spinous process, one above the other.

The first wing 3108 has a lower portion 3113 and an upper portion 3112.As shown in FIG. 32, the upper portion 3112 is shaped to accommodate theanatomical form or contour of spinous processes (and/or laminae) of theL4 (for an L4-L5 placement) or L5 (for an L5-S1 placement) vertebra. Thesame shape or variations of this shape can be used to accommodate othermotion segments. The lower portion 3113 can also be rounded toaccommodate the spinous processes. The lower portion 3113 and upperportion 3112 of the first wing 3108 act as a stop mechanism when theimplant 3100 is inserted between adjacent spinous processes. The implant3100 cannot be inserted beyond the surfaces of the first wing 3108.Additionally, once the implant 3100 is inserted, the first wing 3108 canprevent side-to-side, or posterior-to-anterior movement of the implant3100. The first wing 3108 can further include one or more alignmentholes 3103 and one or more locking pin holes 3104 for receiving pins ofa main body insertion instrument (not shown).

The implant 3100 further includes an adjustable wing 3150 (also referredto herein as a second wing). The adjustable wing 3150 has a lowerportion 3152 and an upper portion 3153. Similar to the first wing 3108,the adjustable wing 3150 is designed to accommodate the anatomical formor contour of the spinous processes and/or lamina. The adjustable wing3150 is secured to the main body 3101 with a fastener 3154. Theadjustable wing 3150 also has an alignment tab 3158. When the adjustablewing 3150 is initially placed on the main body 3101, the alignment tab3158 engages the alignment track 3103. The alignment tab 3158 slideswithin the alignment track 3103 and helps to maintain the adjustablewing 3150 substantially parallel with the first wing 3108. When the mainbody 3101 is inserted into the patient and the adjustable wing 3150 hasbeen attached, the adjustable wing 3150 also can prevent side-to-side,or posterior-to-anterior movement. FIG. 33A illustrates an implant 3100positioned between adjacent spinous processes extending from vertebraeof the lumbar region. The implant 3100 is positioned between inferiorarticular processes 10 associated with the upper vertebrae and superiorarticular processes 12 associated with the lower vertebrae. Thesupraspinous ligament 6 connects the upper and lower spinous processes2,4. The implant 3100 can be positioned without severing or otherwisedestructively disturbing the supraspinous ligament 6.

Referring to FIG. 33B, the spacer 3102 of the implant 3100 of FIG. 33Ais shown in cross-section. The spacer 3102 defines a minimum spacebetween adjacent spinous processes 2,4.

During extension the spacer 3102 limits or blocks relative movementbetween the adjacent spinous processes 2,4, limiting or blocking thecollapse of the space between the spinous processes 2,4. Such supportcan alleviate symptoms of degenerative disorders by preventing areduction of the foraminal area and compression of the nerve roots, orby avoiding aggravation of a herniated disk, or by relieving otherproblems. However, as shown in FIG. 33C, the implant 3100 permitsflexion, which in some degenerative disorders (for example in cases ofspinal stenosis) can relieve some symptoms. As can be seen, duringflexion the spacer 3102 can float between the spinous processes, held inposition by the interspinous ligament 8, and/or other tissues andstructures associated with the spine. The ability to float between thespinous processes 2,4 also permits varying degrees of rotation, as wellas flexion. Implants as described in Zucherman '842 thus have theadvantage that they permit a greater degree of movement when comparedwith primary and supplementary spinal fusion devices.

In some circumstances, for example where a patient develops spondylosisor other degenerative disorder that makes both flexion and extensionpainful and uncomfortable, it can be desired that the spinous processesbe further immobilized, while providing the same ease of implantation asprovided with implants described above. Referring to FIG. 34A, anembodiment of an implant 3300 in accordance with the present inventionis shown. The implant 3300 includes a distraction guide 3306, a spacer3302, and a brace 3308. As shown, the spacer 3302 is rotatable about acentral body 3301 extending from the brace 3302, although in otherembodiments the spacer 3302 can be fixed is position. A binder 3330 canbe fixedly connected with the brace 3308 at a proximal end 3332 of thebinder 3330. The binder 3330 is flexible, or semi-flexible, and can bepositioned around adjacent spinous processes so that the binder 3308engages the spinous processes during flexion of the spine. Oncepositioned around adjacent spinous processes, tension of the binder 3330can be set when the binder 3330 is secured to the brace 3308 so thatrelative movement of the adjacent spinous processes during flexion islimited or prevented, as desired.

As can be seen in FIG. 34A, in an embodiment the brace 3308 can includea first end having a slot 3341 through which the proximal end 3332 ofthe binder 3330 can be threaded and subsequently sutured, knotted orotherwise bound so that the proximal end 3332 of the binder 3330 cannotbe drawn through the slot 3341. In other embodiments (not shown), theproximal end 3332 can be looped or can include a connector, such as aclasp or other device, and can be fixed to the brace 3308 via a fastenerthat engages the connector. One of ordinary skill in the art canappreciate the myriad different ways in which the proximal end 3332 ofthe binder 3330 can be associated with the brace 3308 so that tensioncan be applied to the binder 3330, and implants in accordance with thepresent invention are not intended to be limited to those schemesdescribed in detail herein. The brace 3308 can include a height alongthe spine greater than a height of the spacer 3302 so that movementalong a longitudinal axis L in the direction of insertion is limited orblocked by the brace 3308 when the brace 3308 contacts the lateralsurfaces of the spinous processes. In this way, the brace 3308 canfunction similarly to the wing 3108 of the above described implant 3300.In other embodiments, the brace 3308 can have a height greater orsmaller than as shown. Once the binder 3330 is positioned around thespinous processes and secured, movement of the implant 3300 relative tothe spinous processes is limited by the binder 3330 along thelongitudinal axis as well as along the spinous processes (i.e.,anterior-to-posterior movement).

A free end of the binder 3330 can be secured to the brace 3308 by acapture device 3320 associated with the brace 3308. The brace 3308 caninclude a flange 3310 from which the capture device 3320 can extend, inthe embodiment shown in FIG. 34A, the capture device 3320 comprises arotatable cam 3321 having a fastener 3322 and one or more cut-outs 3324.A tool can be mated with the cut-outs 3324 and rotated to pivot therotatable cam 3321. When the cam 3321 is rotated, the eccentric shape ofthe cam 3321 causes a gap to close between the cam 3321 and a wall 3314of the brace 3330 from which the flange 3310 extends. When the binder3330 is positioned between the cam 3321 and the wall 3314, the rotationof the cam 3321 can pinch the binder 3330 between the cam 3321 and thewall 3314, defining a secured end 3336 of the binder 3330. Optionally,the fastener 3322 can be screwed (i.e., rotated) so that the fastener3322 is further seated, tightening against the cam 3321 to fix the cam3321 in position. Further, optionally, one or both of the wall 3314 andthe rotatable cam 3321 can include knurls, or some other texture (e.g.,teeth) to prevent slippage (i.e., the slipping of the binder 3330between the cam 3321 and the wall 3314). The brace 3308 can furtherinclude a guide 3312, such as a channel or slot (a slot as shown) at asecond end of the brace 3308 to align the binder 3330 with the capturedevice 3320. The binder 3330 can comprise a strap, ribbon, tether, cord,or some other flexible (or semi-flexible), and preferably threadablestructure. The binder 3330 can be made from a biocompatible material, inan embodiment, the binder 3330 can be made from a braided polyestersuture material. Braided polyester suture materials include, forexample, Ethibond, Ethiflex, Mersilene, and Dacron, and arenonabsorbable, having high tensile strength, low tissue reactivity andimproved handling. In other embodiments, the binder 3330 can be madefrom stainless steel (i.e., surgical steel), which can be braided into atether or woven into a strap, for example. In still other embodiments,the binder 3330 can be made from some other material (or combination ofmaterials) having similar properties.

The distraction guide 3306 can optionally include a slot, bore, cut-outor other cavity 3309 formed in the distraction guide 3306 through whichthe binder 3330 can be threaded or positioned. Such a cavity can allowon-axis positioning of the binder 3330 (i.e., the binder can besubstantially aligned with the longitudinal axis L of the implant 3300).Further, capturing the binder 3330 within a slot or bore can prevent orlimit shifting of the distraction guide 3306 relative to the binder 3330to further secure the implant 3300 between the spinous processes.

As will be readily apparent to one of skill in the art, implants inaccordance with the present invention provide significant benefits to aphysician by simplifying an implantation procedure and reducingprocedure time, while providing an implant that can limit or blockflexion and extension of the spine. A physician can position an implantbetween adjacent spinous processes and can position a binder 3330connected with the brace 3308 around the spinous processes withoutrequiring the physician to measure an appropriate length of the binder3330 prior to implantation. The capture device 3320 allows the binder3330 to be secured to the brace 3308 anywhere along a portion of thebinder 3330, the portion being between a distal end 3334 of the binder3330 and the proximal end 3332. The physician can secure the binder 3330to the brace 3308 to achieve the desired range of movement (if any) ofthe spinous processes during flexion.

The capture device 3320 and brace 3308 can have alternative designs tothat shown in FIG. 34A. A side view of an implant 3400 in accordancewith an alternative embodiment of the present invention is shown in FIG.34B, the implant 3400 including a capture device 3420 comprising a cam3421 positioned within a ring 3426 having one or more lobes 3423corresponding with one or more recesses 3413 in a wall 3414 of the brace3408. The binder 3330 is positioned between the capture device 3420 andthe brace 3408. Once the binder 3330 is positioned as desired, thefastener 3422 and cam 3421 can be rotated using an appropriate tool,with the cam 3421 forcing the lobes 3423 of the ring 3426 to mate withthe recesses 3413 of the brace 3408, preventing the ring 3426 fromshifting in position and defining a secure end 3336 of the binder 3330.Rotating the fastener 3422 rotates and optionally tightens down the cam3421. Such a capture device 3420 can provide a physician a visualindication that the binder 3330 is properly secured to the brace 3408,as well as preventing slippage.

Referring to FIGS. 34C and 34D, in still other embodiments, the implantcan include a capture device comprising a spring-loaded mechanism. FIG.34C illustrates an implant 3500 including a capture device 3520comprising a single spring-loaded cam 3521 pivotally connected with theflange 3310 and biased to rotate in one direction. The distance betweenthe pivot point of the cam 3510 and the wall 3314 is sufficiently narrowthat the rotation of the cam 3521 in the direction of bias is blocked(or nearly blocked) by the wall 3314. The eccentricity of the cam 3521is large enough that a maximum gap between the wall 3314 and the cam3521 is sufficiently wide as to allow the binder 3330 to be threadedbetween the cam 3521 and the wall 3314. A physician can position thebinder 3330 between the cam 3521 and the wall 3514 by overcoming thespring-force of the spring-loaded cam 3521. Once the binder 3330 isposition as desired, the physician need only allow the bias force of thespring-loaded cam 3520 to force the cam 3521 against the wall 3314, sothat the cam 3521 pinches and secures the binder 3330 between the cam3521 and the wall 3314. Optionally, one or both of the cam 3521 and thewall 3314 can be knurled or otherwise textured to limit or preventslippage. Further, the wall 3314 can optionally include a recess (notshown) to receive the cam 3521 so that the binder 3330 is pinched withinthe recess (similar to the lobe and recess arrangement of FIG. 34B),thereby further limiting slippage. FIG. 34D illustrates an implant 3600including a capture device 3620 comprising dual spring-loaded cams 3621,the dual spring-loaded cams 3621 being pivotally connected with theflange 3310. The dual spring-loaded cams 3621 are biased in oppositionto one another so that the cams 3621 abut one another, similar to camcleats commonly used for securing rope lines on boats. During surgery,the binder 3330 can be loosely positioned around the adjacent spinousprocesses and threaded between the cams 3621. Tension can be applied tothe binder 3330, as desired, by drawing the binder 3330 through the cams3621. The force of the binder 3330 being pulled through the cams 3621can overcome the bias force to allow the binder 3330 to be tightened,while releasing the binder 3330 can define a secure end 3336 of thebinder 3330 as the cams 3621 swivel together. As above, one or both ofthe cams 3621 can be knurled or otherwise textured to limit or preventslippage.

Embodiments of implants have been described in FIGS. 34A-34D with somelevel of specificity; however, implants in accordance with the presentinvention should not be construed as being limited to such embodiments.Any number of different capture devices can be employed to fix a binderto a brace by defining a secure end of the binder, and such capturedevices should not be construed as being limited to capture devicesincluding cams, as described above. The capture device need only be adevice that allows a physician to fit a binder having a generic size, orestimated size, around adjacent spinous processes with a desired levelof precision in tension.

FIGS. 35A and 35B are an opposite end views of the implant of FIG. 34Apositioned between adjacent spinous processes extending from vertebraeof the lumbar region. The contours of a space between adjacent spinousprocesses can vary between patients, and between motion segments. Arotatable spacer 3302 can rotate to best accommodate the shape of thespace so that the implant 3300 can be positioned as desired along thespinous processes. For example, it can be desirable to position thespacer 3302 as close to the vertebral bodies as possible (or as close tothe vertebral bodies as practicable) to provide improved support. Oncethe implant 3300 is positioned as desired, the binder 3330 can bethreaded through interspinous ligaments associated with motion segments(i.e., pairs of adjacent vertebrae and associated structures andtissues) above and below the targeted motion segment so that the binder3330 is arranged around the upper and lower spinous processes 2,4. Thebinder 3330 can then be threaded through the slot 3312 of the brace 3308and positioned between the capture device 3320 and the brace wall 3314.A first tool (not shown) can be inserted into the incision formed toinsert the implant 3300 between the spinous processes 2,4. Though notshown, the spacer 3302 can include a notch, similar to a notch 3190 ofthe spacer 3102 of FIG. 32, and the brace 3308 can include recesses,similar to recesses 103,104 of the first wing 3108 of FIG. 32, that canbe engaged by the first tool for grasping and releasing the implant 3300during insertion. (See U.S. Pat. No. 6,712,819, which is incorporatedherein by reference.) Alternatively, some other technique for graspingand releasing the implant 3300 can be employed. Once the implant 3300 ispositioned and the binder 3330 is arranged as desired, a second tool(not shown), such as a forked tool having spaced apart tines, can engagethe cam 3321 of the capture device 3320 to rotate the cam 3321, therebysecuring the binder 3330 to the brace 3308. A hex wrench can tightendown the fastener 3322 if desired. Alternatively, a single tool can beemployed to perform both the function of insertion of the implant 3300and rotation of the cam 3321, as depicted in the above referencedpatent. Optionally, the binder 3330 can then be trimmed so that thedistal end 3334 of the binder 3330 does not extend undesirably away fromthe brace 3308.

As can be seen, the spacer 3302 is rotated relative to the distractionguide 3306 and the brace 3308. Because the spacer 3302 can rotaterelative to the distraction guide 3306 and the brace 3308, the brace3308 can be positioned so that the binder 3330 can be arranged aroundthe upper and lower spinous processes 2,4 without twisting the binder3330. The binder 3330 is positioned around the lower spinous process 4,threaded or positioned at least partially within a slot 3309 of thedistraction guide 3306, and positioned around the upper spinous process2 so that the binder 3330 can be secured to the brace 3308, as describedabove.

Implants in accordance with the present invention can enable a physicianto limit or block flexion and extension in a targeted motion segmentwhile minifying invasiveness of an implantation procedure (relative toimplantation procedures of the prior art). However, such implants canalso be used where more extensive implantation procedures are desired.For example, as shown in FIG. 35C, it can be desired that the adjacentspinous processes 2,4 be surgically modified to receive the binder 3330,thereby insuring that the binder 3330 does not shift or slide relativeto the spinous processes 2,4. The binder 3330 is threaded directlythrough the respective spinous processes 2,4 rather than through theinterspinous ligaments of adjacent motion segments. The amount of boneremoved from the spinous processes 2,4 can be reduced where a cord ortether is used as a binder 3330 rather than a strap. While suchapplications fall within the contemplated scope of implants and methodsof implantation of the present invention, such application may notrealize the full benefit that can be achieved using such implants due tothe modification of the bone.

Still another embodiment of an implant 3700 in accordance with thepresent invention is shown in the end view of FIG. 36. In such anembodiment the binder 3430 can comprise a first portion 3431 formed as astrap for arrangement around one of the upper and lower spinousprocesses 2,4, and that tapers to a second portion 3433 formed as acord. The distraction guide 3406 can include a bore 3409 or other cavityfor receiving the second portion 3433. As can be seen in FIG. 37A, oncethe binder 3430 is threaded through the distraction guide 3406, a pad3436 of biocompatible material can be associated with the binder 3430,for example by slidably threading the binder 3430 through a portion ofthe pad 3436, and the pad 3436 can be arranged between the binder 3430and the respective spinous process 2 so that a load applied by thebinder 3430 is distributed across a portion of the surface of thespinous process 2. Referring to FIG. 37B, once the binder 3430 isarranged as desired relative to the adjacent spinous processes 2,4, thebinder 3330 can be secured by the brace 3708. The brace 3708 as shown isstill another embodiment of a brace for use with implants of the presentinvention, in such an embodiment, the brace 3708 includes a capturedevice 3720 comprising a clip including a spring-loaded button 3721having a first hole therethrough and a shell 3723 in which the button3721 is disposed, the shell 3723 having a second hole. A physiciandepresses the button 3721 so that the first and second holes align. Thebinder 3430 can then be threaded through the holes, and the button 3721can be released so that the spring forces the holes to misalign,pinching the binder 3430 and defining a secure end of the binder 3430.

FIG. 37C is an end view of a still further embodiment of an implant 3800in accordance with the present invention. In such an embodiment thebinder 3530 can comprise a cord. An upper pad 3536 and a lower pad 3538can be slidably associated with the binder 3530 and arranged so that aload applied by the binder 3530 is distributed across a portion of theupper and lower spinous processes 2,4. As can be seen, such anembodiment can include a brace 3808 having a substantially differentshape than braces previously described. It should be noted that thebrace 3808 of FIG. 37C is shown, in part, to impress upon one ofordinary skill in the art that a brace and capture device for use withimplants of the present invention can include myriad different shapes,mechanisms and arrangements, and that the present invention is meant toinclude all such variations. As shown, the footprint of the brace 3808is reduced by shaping the wall 3814 of the brace 3808 to taper at anupper end to form a guide 3812 for aligning the binder 3530 and to taperat a lower end to an eyelet 3841 for capturing a proximal end 3532 ofthe binder 3530. The brace 3808 includes a height from eyelet 3841 toguide 3812 such that movement of the implant 3800 in the direction ofinsertion is blocked or limited by the brace 3808.

Use of a binder to limit or prevent flexion can provide an additionalbenefit of limiting movement along the longitudinal axis L (shown inFIG. 34A). However, implants in accordance with the present inventioncan optionally further include a second wing for limiting or blockingmovement in the direction opposite insertion. Inclusion of such astructure can ensure that the implant remains in position, for examplewhere the binder slips out of a slot of the distraction guide, or wherethe binder becomes unsecured.

Referring to FIG. 38A, an implant in accordance with an embodiment caninclude a second wing 3450 connected with the distraction guide 3406 ofthe implant 3900 by a fastener 3454. The second wing 3450 is similar tothe second wing 3150 described above in reference to FIG. 32. The secondwing 3450 can include an alignment tab 3458 allowing a position of thesecond wing 3450 to be adjusted along a longitudinal axis L of theimplant 3900, and a fastener 3454 (for example a hex headed bolt) foraffixing the second wing 3450 to the implant 3900 in the position alongthe longitudinal axis L desired. The distraction guide 3406 can includean alignment groove (not shown) corresponding to the alignment tab 3458.The alignment tab 3458 fits within, and is movable along, the alignmentgroove so that a contact surface 3455 of the second wing 3450 can bearranged as desired. As shown, the second wing 3450 includes asubstantially planar contact surface arranged so that the contactsurface 3455 of the second wing 3450 is perpendicular to thelongitudinal axis L. However, in other embodiments, the contact surface3455 need not be planar, and can be shaped and oriented to roughlycorrespond with a contact surface of the upper and lower spinousprocesses. Likewise, a contact surface 3315 of the binder 3308 can beshaped and oriented to roughly correspond with a contact surface of theupper and lower spinous processes. As shown, the upper portion 3453 andthe lower portion 3452 of the second wing 3450 do not extend from thedistraction guide 3406 as substantially as the upper portion 3153 andlower portion 3152 of the second wing 3150 of FIG. 32. As such, thesecond wing 3450 includes a height H along the spine smaller than thatof the second wing 3150 of FIG. 32. It has been observed that benefitscan be gained by including a wing 3450, though the wing 3450 does notextend from the distraction guide 3406 as significantly as shown in FIG.32 (i.e., the wing 3450 includes “nubs” extending above and/or below theheight of the spacer 3302). Such wings 3450 will also be referred toherein as winglets. Including a second wing 3450 having an overallheight along the spine smaller than that of FIG. 32 can limit movementalong the longitudinal axis without interfering with (or beinginterfered by) the arrangement of the binder 3330.

In other embodiments, implants in accordance with the present inventioncan include a second wing (or an upper portion and/or lower portion)extendable from the distraction guide. In this way an implant and adevice for limiting or blocking movement along a longitudinal axis ofthe implant can be included in a single piece, possibly simplifyingimplantation. Referring to FIGS. 38B and 38C, implants 1500 inaccordance with the present invention can include a distraction guide3506 having a selectably extendable upper portion 3553 and lower portion3552 disposed within a cavity of the distraction guide 3506. The upperand lower portions 3553,3552 can be extended by actuating a nut, knob orother mechanism operably associated with a gear 3556 so that the gear3556 rotates. The teeth of the gear 3556 engage teeth of the upper andlower portions 3553,3552, causing the upper and lower portions 3553,3552to extend sufficiently that the upper and lower portions 3553,3552 formwinglets for preventing motion of the implant 1500 in a directionopposite insertion (shown in FIG. 38C). Rotating the gear 3556 in anopposite direction can retract the upper and lower portions 3553,3552.

In an alternative embodiment, implants 1600 in accordance with thepresent invention can include spring-loaded upper and/or lower portions3653,3652 such as shown in FIGS. 38D and 38E. In such an embodiment theupper and lower portions 3653,3652 can be fin-shaped, having slopingforward surfaces 3655,3654 and being spring-biased to an extendedposition, as shown in FIG. 38D. As the implant 1600 is positionedbetween adjacent spinous processes, the spinous processes and/or relatedtissues can contact the forward surface 3655,3654 of the upper and lowerportions 3653,3652, causing the upper and lower portions 3653,3652 topivot about respective hinge points 3657,3656 and collapse into cavitiesdisposed within the distraction guide 3606, as shown in FIG. 38E. Oncethe implant 1600 clears the obstruction, the upper and lower portions3653,3652 re-extend out of the distraction guide 3650. A slot and pinmechanism 3660,3661 or other mechanism can lock the upper and lowerportion 3653,3652 in place once extended, disallowing over-extension ofthe upper and lower portion 3653,3652 in the direction of bias. Theextended upper and lower portions 3653,3652 limit or block movement ofthe implant 1600 in an a direction opposite insertion.

In still further embodiments, implants in accordance with the presentinvention can optionally employ some other additional mechanism forlimiting or blocking motion along the longitudinal axis of the implant.Mechanisms shown and described in FIGS. 38A-38E are merely provided asexamples of possible mechanisms for use with such implants, and are notintended to be limiting.

FIG. 39 is a top-down view of still another embodiment of an implant inaccordance with the present invention including a brace 3708 arranged atan angle along the spinous process relative to the longitudinal axis Lof the implant 1700. The brace 3708 is arranged at such an angle toroughly correspond to a general shape of the adjacent spinous processes.Such a general shape can commonly be found in spinous processesextending from vertebrae of the cervical and thoracic region, forexample. The implant 1700 further includes a second wing 3752 extendingfrom distraction guide 3706 at an angle roughly corresponding to ageneral shape of the adjacent spinous processes. Identical implants1700, one above the other, are shown. The lower implant 1700 includes abinder 3330 arranged around the adjacent spinous processes (only theupper spinous process is shown) and positioned in a slot 3309 of thedistraction guide 3706. The binder 3330 includes a capture device 3320for securing the binder 3330 to the brace 3708, and a channel formed byguides 3712 on the brace 3708 for aligning the binder 3330 with thecapture device 3320. Unlike previously illustrated embodiments, thebrace wall includes a recess 3717 to accommodate rotation of therotatable spacer 3302. Alternatively, the implants can include fixedspacers, for example integrally formed with the brace 3708 and thedistraction guide 3706.

FIGS. 40A and 40B are perspective views, and FIG. 40C is a side view ofa still further embodiment of an implant in accordance with the presentinvention. The implant 2600 includes a distraction guide 806, arotatable spacer 3302, and a brace 3908. As above, a binder 3330 can befixedly connected with the brace 3908 at a proximal end 3332 of thebinder 3330. Once positioned around adjacent spinous processes, tensionof the binder 3330 can be set when the binder 3330 is secured to thebrace 3908 so that relative movement of the adjacent spinous processesduring flexion is limited or prevented, as desired.

As can be seen in FIG. 40A, the brace 33908 can include a first endhaving an eyelet 3941 through which the proximal end 3332 of the binder3330 can be threaded and subsequently sutured, knotted or otherwisebound, or alternatively looped through the eyelet 3941 and secured toitself (e.g., using a clasp) so that the proximal end 3332 of the binder3330 cannot be drawn through the eyelet 3941. One of ordinary skill inthe art can appreciate the myriad different ways in which the proximalend 3332 of the binder 3330 can be associated with the brace 3908 sothat tension can be applied to the binder 3330. As in previousembodiments, a free end of the binder 3330 can be secured to the brace3908 by a capture device 3820 associated with the brace 3908. Thecapture device 3820 of FIGS. 40A-42 is arranged at a second end of thebrace 3908 opposite the eyelet 3941, rather than approximately centeredalong the brace wall 3914. The brace 3908 can optionally include alocking pin hole 3915 that can be engaged by a locking pin of aninsertion instrument (not shown), for example as described in U.S. Pat.No. 6,712,819 to Zucherman, et al., incorporated herein by reference.Further, similar to implants described in Zucherman '819, the brace wall3914 can optionally include one or more holes 3916 (shown in FIG. 42)adapted to receive alignment pins of such an insertion instrument, andthe spacer 3402 can include a spacer engagement hole 3403 adapted toreceive a spacer engagement pin of such an insertion instrument. When aspacer engagement pin engages the spacer engagement hole 3403, rotationof the spacer 3402 can be limited or blocked. Once the spacer engagementpin is released from the spacer engagement hole 3403, the spacer 3402can rotate and/or swivel about a central body 3917 without impedancefrom the spacer engagement pin. Such an arrangement can provide aphysician additional control over the positioning of the implant 2600,although in other embodiments the spacer 3402 need not include anengagement hole 3403. Arranging the captured device 3820 at a second endof the brace 3908 can allow an insertion instrument, having aconfiguration as described in Zucherman '819 or having some otherconfiguration, to releasably engage the implant 2600 to assist inimplantation without interference from the capture device 3820.

The distraction guide 3806 of the implant 2600 can be wedge-shaped, asdescribed above, or approximately conical, as shown in FIGS. 40A-40C,and can include a slot 3809 disposed through the distraction guide 3806and adapted to receive the binder 3330 during implantation. Also asdescribed above, the rotatable spacer 3402 can be elliptical incross-section, or otherwise shaped, and can rotate relative to thedistraction guide 3806 to roughly conform with a contour of a spacebetween the targeted adjacent spinous processes.

The capture device 3820 is shown in cross-section in FIGS. 41A and 41B.The capture device 3820 can comprise, for example, two pieces slidablyassociated with one another by an adjustable fastener 3822 (as shown,the adjustable fastener is a hex screw). A fixed piece 3821 of thecapture device can extend from the brace wall 3914. The fixed piece 3821can include a beveled surface 3823 that can function as a ramp. Aslidable piece 3827 of the capture device can be slidably associatedwith the fixed piece 3821, and can likewise included a beveled surface3829 positioned in opposition to the beveled surface 3823 of the fixedpiece 3821. As shown, the slidable piece 3827 is associated with thefixed piece 3821 via an adjustable fastener 3822. The fastener 3822 canbe positioned within slots 3890,3892 of the fixed piece 3821 and theslidable piece 3827 and can include a threaded shaft 3880, a head 3882,and a nut 3884. The head 3882 of the fastener 3822 can engage ananterior surface 3894 of the fixed piece 3821 and the nut 3884 can bethreaded onto the threaded shaft 3880 so that the nut 3884 can engage aposterior surface 3896 of the slidable piece 3827. The slidable piece3827 is free to slide along the beveled surface 3823 of the fixed piece3821 until both the nut 3884 engages the posterior surface 3896 and thehead 3882 engages the anterior surface 3894, blocking further movementin one direction. The distance between the anterior surface 3894 and theposterior surface 3896 increases or decreases as the slidable piece 3827slides along the beveled surface 3823 and a distance between a capturesurface 3898 of the slidable piece 3827 and the brace wall 3914 likewiseincreases or decreases. The maximum distance the slidable piece 3827 cantravel can be defined by the distance between the nut 3884 and the head3882. A physician can adjust the maximum distance by rotating the nut3884 so that the nut 3884 travels closer to, or farther from the head3882 along the threaded shaft 3880, possibly urging the capture surface3898 toward the brace wall 3914. Thus, when the implant 2600 ispositioned between spinous processes, the physician can set the maximumdistance so that the free end of the binder 3330 can be threaded betweenthe capture surface 3898 and the brace wall 3914. As shown in FIG. 41B,the physician can then adjust the fastener 3822 so that the posteriorsurface 3896 and the anterior surface 3894 are urged together, themaximum distance decreases and the distance between the capture surface3898 and the brace wall 3914 decreases, thereby pinching the binder 3330between the capture surface 3898 and the brace wall 3914 and defining asecure end of the binder 3330. In some embodiments, one or both of thecapture surface 3898 and the brace wall 3914 can include texture so thatthe binder 3330 is further prevented from sliding when the binder 3330is placed under increasing tension (e.g., during flexion).

The slidable piece 3827 can optionally further include a guide 3912extending from the slidable piece 3827 so that the guide 3912 overlaps aportion of the brace 3908. The guide 3912 can extend, for example, adistance roughly similar to the maximum distance between the capturesurface 3898 and the brace wall 3914, and can help ensure that thebinder 3330 is captured between the capture surface 3898 and the bracewall 3914. In other embodiments, the capture device 3820 of FIGS.40A-41B can include some other shape or configuration and still fallwithin the contemplated scope of the invention. For example, thefastener need not include a nut. In one embodiment, shown in FIGS. 41Cand 41D, the fastener 3922 can include a threaded shaft 3980 associatedwith a sleeve 3984. As one of the threaded shaft 3980 and the sleeve3984 is rotated, the distance between a head 3982 of the threaded shaft3980 and the head 3985 of the sleeve 3984 can decrease or increase. Instill other embodiments, the fastener need not include a threaded shaft,but rather can include a smooth shaft having a retaining clipfrictionally associated with the smooth shaft. One of ordinary skill inthe art will appreciate the myriad different devices that can beemployed to selectively close a gap between a capture surface 3898 andthe brace wall 3914.

FIG. 42 is an end view of the implant 2600 of FIGS. 40A-41D positionedbetween adjacent spinous processes. As shown, the binder 3530 is a cord,but in other embodiments can have some other geometry. As describedabove in reference to previous embodiments, where a cord, a tether, orthe like is used as a binder, a pad 3536 can be arranged along a contactsurface of the respective spinous process so that a load applied to thecontact surface by the tension in the binder 3530 can be distributedacross a portion of the contact surface wider than the binder 3530,thereby reducing stress on the portion. The capture device 3820 isarranged so that the slidable piece 3827 is posteriorly located relativeto the fixed piece 3821. A fastener 3822 can be accessed by thephysician using a substantially posterior approach.

A method of surgically implanting an implant 2600 in accordance with anembodiment as described above in FIGS. 40A-42 of the present inventionis shown as a block diagram in FIG. 43. The method can include formingan incision at the target motion segment, and enlarging the incision toaccess the target motion segment (Step 2700). The interspinous ligamentbetween targeted adjacent spinous processes can then be distracted bypiercing or displacing the interspinous ligament with the distractionguide 3106 (Step 2702) and urging the implant 2600 between the adjacentspinous processes (Step 2704). As the interspinous ligament isdisplaced, the spacer 3302 can be positioned between the spinousprocesses such that the spacer 3302 can rotate to assume a preferredposition between the spinous processes (Step 2706).

Once the implant 2600 is positioned, the binder 3330 can be threadedbetween interspinous ligaments of adjacent motion segments so that thetargeted adjacent spinous processes are disposed within a loop formed bythe binder 3330 (Step 2708). The physician can then thread the binder3330 between the capture surface 3898 of the capture device 3820 and thebrace wall 3914 (Step 2710). Once a desired tension of the binder 3330is applied (Step 2712), the physician can adjust the fastener 3822 ofthe capture device 3820 so that the binder 3330 is secured between thecaptured surface 3898 and the brace wall 3914 (Step 2714). The incisioncan subsequently be closed (Step 2716).

FIGS. 44A and 44B are perspective views of still another embodiment ofan implant 5400 in accordance with the present invention. In such anembodiment, the implant 5400 can include a main body 3101 similar to themain body 3101 described above in reference to FIG. 32. As above, themain body 3101 (also referred to herein as a first unit) includes aspacer 3102, a first wing 3108, a distraction guide 3106 and analignment track 3103. The main body 3101 is inserted between adjacentspinous processes. Preferably, the main body 3101 remains (wheredesired) in place without attachment to the bone or ligaments.

The alignment track 3103 includes a threaded hole for receiving afastener. The alignment track 3103 need not include a threaded hole, butrather alternatively can include some other mechanism for fixedlyconnecting an additional piece (such as a second wing for limiting orblocking movement of an implant along the longitudinal axis). Forexample, in an alternative embodiment, the alignment track 5403 caninclude a flange so that the second wing 5450 can be slidably received,as shown in FIG. 46.

As further shown in FIGS. 44A and 44B, the implant 5400 includes asecond wing 5450 removably connectable with the implant 5400. The secondwing 5450 includes an alignment tab 5458 adapted to be received in thealignment track 3103 of the main body 3101, the alignment tab 5458optionally including a slot for receiving the fastener so that thealignment tab 5458 is disposed between the fastener and the alignmenttrack 3103. In alternative embodiments, the alignment tab 5458 need notinclude a slot but rather can include some other mechanism for matingwith the main body 3101. The second wing 5450 can include a first endhaving a slot (or eyelet) 5441 through which the proximal end (alsoreferred to herein as an anchored end) 3332 of a binder 3330 can bethreaded and subsequently sutured, knotted or otherwise bound, oralternatively looped through the slot 5441 and secured to itself (e.g.,using a clasp) so that the proximal end 3332 of the binder 3330 cannotbe withdrawn through the slot 5441. One of ordinary skill in the art canappreciate the myriad different ways in which the proximal end 3332 ofthe binder 3330 can be associated with the second wing 5450 so thattension can be applied to the binder 3330. The binder 3330 can bedisposed around adjacent spinous processes and a portion of the lengthof the binder 3330 (the length of the binder being that portion of thebinder extending from the proximal end of the binder) can be secured tothe second wing 5450 by a capture device 5420 associated with the secondwing 5450.

The capture device 3820 of FIGS. 44A and 44B is arranged at a second endof the second wing 5450 opposite the slot 5441. The capture device 5420can be substantially similar to capture devices 5420 as described abovein reference to FIGS. 41A and 41B, and can comprise, for example, twopieces slidably associated with one another by an adjustable fastener.As above, a fixed piece 5421 of the capture device can extend from thesecond wing 5450. The fixed piece 5421 can include a beveled surfacethat can function as a ramp. A slidable piece 5427 of the capture devicecan be slidably associated with the fixed piece 5421 (for example, viathe adjustable fastener) and can likewise included a beveled surfacepositioned in opposition to the beveled surface of the fixed piece 5421.As the slidable piece 5427 slides along the beveled surface of the fixedpiece 5421, a distance between a capture surface 5498 of the slidablepiece 5427 and the second wing 5450 increases or decreases. As above,the slidable piece 5427 can optionally further include a guide 5412extending from the slidable piece 5427 so that the guide 5412 overlaps aportion of the second wing 5450. The guide 5412 can extend, for example,a distance roughly similar to the maximum distance between the capturesurface 5498 and the second wing 5450, and can help ensure that thebinder 3330 is arranged between the capture surface 5498 and the secondwing 5450. A physician can position the binder 3330 so that the binder3330 is disposed between adjacent spinous processes, threading thebinder 3330 between the slidable piece 5427 and the second wing 5450.The physician can then adjust the fastener 5422 so that the distancebetween the capture surface 5498 and the second wing 5450 decreases,thereby pinching the binder 3330 between the capture surface 5498 andthe second wing 5450 and defining a secure end of the binder 3330. Insome embodiments, one or both of the capture surface 5498 and the secondwing 5450 can include texture so that the binder 3330 is furtherprevented from sliding when the binder 3330 is placed under increasingtension (e.g., during flexion).

The implant 5400 can further include a binder aligner 5470 selectablyconnectable with the first wing 3108 of the main body 3101. The binderaligner 5470 can be connected with the first wing 3108 by fastening thebinder aligner 5470 to the locking pin hole 3104 of the first wing 3108.In such embodiments where a fastener 5455 is used to connect the binderaligner 5470 with the first wing 3108 through a hole 5471 in the binderaligner 5470, it is desirable that the locking pin hole 3104 bethreaded, or otherwise adapted to receive the fastener 5455. The lockingpin hole 3104 can thus be adapted to function as a hole to slidably (andtemporarily) receive a locking pin of an insertion tool (not shown),thereby facilitating insertion and positioning of the main body 3101,and can also be adapted to function to fixedly receive a fastener 5455for positioning the binder aligner 5470. The binder aligner 5470 canoptionally include pins 5474 corresponding to the alignment holes 3192of the main body 3101 to further secure the binder aligner 5470 to themain body 3101 and limit undesired movement of the binder aligner 5470relative to the main body 3101.

The binder aligner 5470 includes a guide 5472 extending from the binderaligner 5470 to limit or block shifting of the binder 3330 in aposterior-anterior direction. The guide 5472 can include a loop, asshown in FIG. 44A, or alternatively some other structure, closed orunclosed, for limiting or blocking shifting of the binder 3330. Such astructure can prevent undesired relative movement between the binder3330 and the main body 3101, and can additionally ease arrangement ofthe binder 3330 during an implantation procedure, by helping to aidproper positioning of the binder 3330.

In other embodiments, the capture device of FIGS. 44A and 44B caninclude some other shape, configuration, and mechanism and still fallwithin the contemplated scope of the invention. For example, referringto FIG. 45, in other embodiments, a flange 5514 can extend from thesecond wing 5550, from which a rotatable cam 5521 extends so that thebinder 3330 can be captured between the second wing 5550 and the cam5521. Such a capture device can resemble capture devices 5520 asdescribed above in FIGS. 34C and 34B. Referring to FIG. 46, in stillother embodiments, a spring-loaded cam 5621 extends from the flange 5514so that the binder 3330 can be captured between the second wing 5514 andthe spring-loaded cam 5621. Such a capture device can resemble capturedevices 5520 as described above in FIGS. 34C and 34D. In still furtherembodiments in accordance with the present invention, some othermechanism can be employed as a capture device associated with the secondwing 5550 for securing the length of the binder 3330, for example asotherwise described in herein, and other obvious variations. One ofordinary skill in the art will appreciate the myriad differentmechanisms for securing the binder 3330 to the second wing 5450. Asystem in accordance with the present invention can comprise a secondwing 5450 including a capture device 5420 as described above andoptionally a binder aligner 5470. The system can be used with a mainbody 3101 in substitution for a second wing 3150 as described above inFIG. 32. Alternatively, the system can optionally be used to modify amain body 3101 previously implanted in a patient, for example byremoving an existing second wing 3150 and replacing the second wing 3150with the system, to additionally limit flexion as well as extension.Such a system can provide flexibility to a physician by allowing thephysician to configure or reconfigure an implant according to the needsof a patient. Further, such a system can reduce costs by reducing thevariety of components that need be manufactured to accommodate differentprocedures and different treatment goals. A method of surgicallyimplanting an implant 5400 in accordance with an embodiment as describedabove in FIGS. 44A-46 of the present invention is shown as a blockdiagram in FIG. 47. The method can include forming an incision at thetarget motion segment, and enlarging the incision to access the targetmotion segment (Step 2700). The interspinous ligament between targetedadjacent spinous processes can then be distracted by piercing ordisplacing the interspinous ligament with the distraction guide 106(Step 2702) and urging the implant 5400 between the adjacent spinousprocesses (Step 2704). As the interspinous ligament is displaced, thespacer 3102 can be positioned between the spinous processes such thatthe spacer 3102 can rotate to assume a preferred position between thespinous processes (Step 2706).

Once the implant 5400 is positioned, the second wing 5450 can be fixedlyconnected with the distraction guide 3106 (Step 2708). A binder 3330associated with the second wing 5450 can be threaded betweeninterspinous ligaments of adjacent motion segments so that the targetedadjacent spinous processes are disposed within a loop formed by thebinder 3330 (Step 2710).

The physician can then thread the binder 3330 between the capturesurface 5498 of the capture device 5420 and the second wing 5450 (Step2712). Once a desired tension of the binder 3330 is applied (Step 2714),the physician can adjust the fastener 5422 of the capture device 5420 sothat the binder 3330 is secured between the captured surface 5498 andthe second wing 5450 (Step 2716). The incision can subsequently beclosed (Step 2718).

Material for Use in Implants of the Present Invention

In some embodiments, the implant can be fabricated from medical grademetals such as titanium, stainless steel, cobalt chrome, and alloysthereof, or other suitable implant material having similar high strengthand biocompatible properties. Additionally, the implant can be at leastpartially fabricated from a shape memory metal, for example Nitinol,which is a combination of titanium and nickel. Such materials aretypically radiopaque, and appear during x-ray imaging, and other typesof imaging. Implants in accordance with the present invention, and/orportions thereof can also be fabricated from somewhat flexible and/ordeflectable material, m these embodiments, the implant and/or portionsthereof can be fabricated in whole or in part from medical gradebiocompatible polymers, copolymers, blends, and composites of polymers.A copolymer is a polymer derived from more than one species of monomer.A polymer composite is a heterogeneous combination of two or morematerials, wherein the constituents are not miscible, and thereforeexhibit an interface between one another. A polymer blend is amacroscopically homogeneous mixture of two or more different species ofpolymer. Many polymers, copolymers, blends, and composites of polymersare radiolucent and do not appear during x-ray or other types ofimaging. Implants comprising such materials can provide a physician witha less obstructed view of the spine under imaging, than with an implantcomprising radiopaque materials entirely. However, the implant need notcomprise any radiolucent materials.

One group of biocompatible polymers is the polyaryletherketone groupwhich has several members including polyetheretherketone (PEEK), andpolyetherketoneketone (PEKK).

PEEK is proven as a durable material for implants, and meets thecriterion of biocompatibility. Medical grade PEEK is available fromVictrex Corporation of Lancashire, Great Britain under the product namePEEK-OPTIMA. Medical grade PEKK is available from Oxford PerformanceMaterials under the name OXPEKK, and also from CoorsTek under the nameBioPEKK. These medical grade materials are also available as reinforcedpolymer resins, such reinforced resins displaying even greater materialstrength, in an embodiment, the implant can be fabricated from PEEK450G, which is an unfilled PEEK approved for medical implantationavailable from Victrex. Other sources of this material include Ghardalocated in Panoli, India. PEEK 450G has the following approximateproperties:

Property Value Density 1.3 g/cc Rockwell M 99 Rockwell R 126 TensileStrength 97 MPa Modulus of Elasticity 3.5 GPa Flexural Modulus 4.1 GPa

PEEK 450G has appropriate physical and mechanical properties and issuitable for carrying and spreading a physical load between the adjacentspinous processes. The implant and/or portions thereof can be formed byextrusion, injection, compression molding and/or machining techniques.

It should be noted that the material selected can also be filled.Fillers can be added to a polymer, copolymer, polymer blend, or polymercomposite to reinforce a polymeric material. Fillers are added to modifyproperties such as mechanical, optical, and thermal properties. Forexample, carbon fibers can be added to reinforce polymers mechanicallyto enhance strength for certain uses, such as for load bearing devices.In some embodiments, other grades of PEEK are available and contemplatedfor use in implants in accordance with the present invention, such as30% glass-filled or 30% carbon-filled grades, provided such materialsare cleared for use in implantable devices by the FDA, or otherregulatory body. Glass-filled PEEK reduces the expansion rate andincreases the flexural modulus of PEEK relative to unfilled PEEK. Theresulting product is known to be ideal for improved strength, stiffness,or stability. Carbon-filled PEEK is known to have enhanced compressivestrength and stiffness, and a lower expansion rate relative to unfilledPEEK. Carbon-filled PEEK also offers wear resistance and load carryingcapability.

As will be appreciated, other suitable similarly biocompatiblethermoplastic or thermoplastic polycondensate materials that resistfatigue, have good memory, are flexible, and/or deflectable, have verylow moisture absorption, and good wear and/or abrasion resistance, canbe used without departing from the scope of the invention. As mentioned,the implant can be comprised of polyetherketoneketone (PEKK). Othermaterial that can be used include polyetherketone (PEK),polyetherketoneetherketoneketone (PEKEKK), polyetheretherketoneketone(PEEKK), and generally a polyaryletheretherketone. Further, otherpolyketones can be used as well as other thermoplastics. Reference toappropriate polymers that can be used in the implant can be made to thefollowing documents, all of which are incorporated herein by reference.These documents include: PCT Publication WO 02/02158 A1, dated Jan. 10,2002, entitled “Bio-Compatible Polymeric Materials;” PCT Publication WO02/00275 A1, dated Jan. 3, 2002, entitled “Bio-Compatible PolymericMaterials;” and, PCT Publication WO 02/00270 A1, dated Jan. 3, 2002,entitled “Bio-Compatible Polymeric Materials.” Other materials such asBionate®, polycarbonate urethane, available from the Polymer TechnologyGroup, Berkeley, Calif., may also be appropriate because of the goodoxidative stability, biocompatibility, mechanical strength and abrasionresistance. Other thermoplastic materials and other high molecularweight polymers can be used.

As described above, the binder can be made from a biocompatiblematerial. In an embodiment, the binder can be made from a braidedpolyester suture material. Braided polyester suture materials include,for example, Ethibond, Ethiflex, Mersilene, and Dacron, and arenonabsorbable, having high tensile strength, low tissue reactivity andimproved handling. In other embodiments, the binder can be made fromstainless steel (i.e., surgical steel), which can be braided into atether or woven into a strap, for example. In still other embodiments,the binder can be made from some other material (or combination ofmaterials) having similar properties. The foregoing description of thepresent invention have been presented for purposes of illustration anddescription. It is not intended to be exhaustive or to limit theinvention to the precise forms disclosed. Many modifications andvariations will be apparent to practitioners skilled in this art. Theembodiments were chosen and described in order to best explain theprinciples of the invention and its practical application, therebyenabling others skilled in the art to understand the invention forvarious embodiments and with various modifications as are suited to theparticular use contemplated. It is intended that the scope of theinvention be defined by the following claims and their equivalents.

Interspinous Implants

FIG. 48A is a perspective view of an implant as described in U.S. patentapplication Ser. No. 10/850,267, filed May 20, 2004, incorporated hereinby reference. The implant 4100 comprises a first wing 4130, a spacer4120, and a lead-in tissue expander (also referred to herein as adistraction guide) 4110.

The distraction guide 4110 in this particular embodiment iswedge-shaped, i.e., the implant has an expanding cross-section from aproximal end of the implant 100 to a region 4150 where the guide 4110joins with the spacer 4120 (referencing for the figures is based on thepoint of insertion of the implant between spinous processes). As such,the distraction guide 4110 functions to initiate distraction of the softtissue and the spinous processes when the implant 4100 is surgicallyinserted between the spinous processes. It is to be understood that thedistraction guide 4110 can be pointed and the like, in order tofacilitate insertion of the implant 4100 between the spinous processesof adjacent cervical vertebrae. It is advantageous that the insertiontechnique disturb as little of the bone and surrounding tissue orligaments as possible in order to reduce trauma to the site and promoteearly healing, and prevent destabilization of the normal anatomy. Forembodiments such as those of FIGS. 48A and 48B, there is no requirementto remove any of the bone of the spinous processes and no requirement tosever, or remove from the body, ligaments and tissues immediatelyassociated with the spinous processes. For example, it is unnecessary tosever the supraspinal ligament of the lower vertebrae or the ligamentumnuchae (which corresponds to the supraspinal ligament) which partiallycushions the spinous processes of the upper cervical vertebrae.

As can be seen, the spacer 4120 can be teardrop-shaped in cross-sectionperpendicular to a longitudinal axis 4125 of the implant 4100. In thisway, the shape of the spacer 4120 can roughly conform to a wedge-shapedspace, or a portion of the space, between adjacent spinous processeswithin which the implant 4100 is to be positioned. As shown in FIG. 48A,the spacer 4120 (and the first wing 4108) is shaped to accommodate theanatomical form or contour of spinous processes (and/or laminae) ofpreferably the C6 and C7 vertebra for placement between such spinousprocesses (i.e., the C6-C7 motion segment). The same shape or variationsof this shape can be used to accommodate other motion segments, forexample in the thoracic or lumbar regions. In other embodiments thespacer 4120 can have alternative shapes such as circular, wedge, oval,ovoid, football, and rectangular with rounded corners, and other shapes.The shape of the spacer 4120 can be selected for a particular patient sothat the physician can position the implant 4100 as close as possible tothe anterior portion of the surface of the spinous process. The shapeselected for the spacer 4120 can affect the contact surface area of theimplant 4100 and the spinous processes that are to be subject todistraction. Increasing the contact surface area between the implant4100 and the spinous processes can distribute a load force between thespinous frame and the implant 4100.

The first wing 4130 is likewise teardrop-shaped in cross-sectionperpendicular to a longitudinal axis 4125 of the spacer 4120 anddistraction guide 4110. The dimensions of the first wing 4130 can belarger than that of the spacer 4120, particularly along the axis of thespine, and can limit or block lateral displacement of the implant 4100in the direction of insertion along the longitudinal axis 4125. As withthe spacer 4120, the first wing 4130 can have other cross-sectionalshapes, such as elliptical, wedge, circular, oval, ovoid, football, andrectangular with rounded corners and other shapes.

The implant 4100 of FIG. 48A further includes an adjustable wing 4160(also referred to herein as a second wing) separate from the distractionguide 4110, the spacer 4120 and the first wing 4130. The second wing4160 is connectable with the distraction guide 4110 (and/or the spacer4120) once the implant 4100 is positioned between adjacent spinousprocesses. The second wing 4160, similar to the first wing 4130, canlimit or block lateral displacement of the implant 4100, howeverdisplacement is limited or blocked in the direction opposite insertion.When both the first wing 4130 and the second wing 4160 are connectedwith the implant 4100 and the implant 4100 is positioned betweenadjacent spinous processes, a portion of the spinous processes can besandwiched between the first wing 4130 and the second wing 4160,limiting displacement along the longitudinal axis 4125. As can be seen,the second wing 4160 can be teardrop-shaped in cross-section. A lip 4180defining a space 4170 through the second wing 4160 allows the secondwing 4160 to pass over the distraction guide 4110 to meet and connectwith the distraction guide 4110 and/or the spacer 4120. The second wing4160 is then secured to the distraction guide 4110 and/or the spacer4120. The second wing 4160, can be designed to be interference-fit ontothe spacer 4120 or a portion of the distraction guide 4110 adjacent tothe spacer 4120. Where the second wing 4160 is interference-fit, thereis no additional attachment device to fasten the second wing 4160relative to the remainder of the implant 4100.

Alternatively, various fasteners can be used to secure the second wing4160 relative to the remainder of the implant 4100. For example, FIG.48A illustrates an embodiment of an implant 4100 including ateardrop-shaped second wing 4160 having a tongue 4158 at the posteriorend of the second wing 4160. A bore 4155 is disposed through the tongue4158, and is aligned with a corresponding bore 4156 on the spacer 4120when the second wing 4160 is brought into position by surgical insertionrelative to the rest of the implant 4100. A threaded screw 4154 can beinserted through the aligned bores 4155,4156 in a posterior-anteriordirection to secure the second wing 4160 to the spacer 4120. Thedirection of insertion from a posterior to an anterior direction has thescrew 4154 engaging the bores 4155,4156 and the rest of the implant 4100along a direction that is generally perpendicular to the longitudinalaxis 4125. This orientation is most convenient when the physician isrequired to use a screw 4154 to secure the second wing 4160 to the restof the implant 4100. The second wing 4160 can further be secured to thespacer 4120 by some other mechanism, for example such as a flexiblehinge (not shown) with a protrusion that engages an indentation of oneof the distraction guide 4110 and the spacer 4120. Alternatively, thesecond wing 4160 can be secured to one of the distraction guide 4110 andthe spacer 4120 by still some other mechanism.

FIG. 48B is a perspective view of an implant as described in U.S. Pat.No. 6,695,842 to Zucherman, et al, incorporated herein by reference. Theimplant 4200 has a main body that includes a spacer 4220, a first wing4230, a lead-in tissue expander 4210 (also referred to herein as adistraction guide) and an alignment track 4203. The main body of theimplant 4200 is inserted between adjacent spinous processes and remainsin place (where desired) without attachment to the bone or ligaments.The distraction guide 4210 includes a tip from which the distractionguide 4210 expands, the tip having a diameter sufficiently small suchthat the tip can pierce an opening in an interspinous ligament and/orcan be inserted into a small initial dilated opening. The diameterand/or cross-sectional area of the distraction guide 4210 graduallyincreases until it is substantially similar to the diameter of thespacer 4220. The tapered front end eases the ability of a physician tourge the implant 4200 between adjacent spinous processes. When urgingthe main body of the implant 4200 between adjacent spinous processes,the front end of the distraction guide 4210 distracts the adjacentspinous processes and dilates the interspinous ligament so that a spacebetween the adjacent spinous processes is approximately the diameter ofthe spacer 4220.

As shown in FIG. 48B, the spacer 4220 is elliptically shaped incross-section, and can swivel so that the spacer 4220 can self-alignrelative to the uneven surfaces of the spinous processes. Self-alignmentcan ensure that compressive loads are distributed across the surface ofthe bone. As contemplated in Zucherman '842, the spacer 4220 can have,for example, a diameter of six millimeters, eight millimeters, tenmillimeters, twelve millimeters and fourteen millimeters. Thesediameters refer to the height by which the spacer 4220 distracts andmaintains apart the spinous process. For an elliptically shaped spacer4220, the selected height (i.e., diameter) is the minor dimensionmeasurement across the ellipse. The major dimension is transverse to thealignment of the spinous process, one above the other.

The first wing 4230 has a lower portion 4231 and an upper portion 4232.The upper portion 4232 is shaped to accommodate the anatomical form orcontour of spinous processes (and/or laminae) of preferably the L4 (foran L4-L5 placement) or L5 (for an L5-S1 placement) vertebra. The sameshape or variations of this shape can be used to accommodate othermotion segments, such as motion segments in the cervical and thoracicregions. The lower portion 4231 can also be rounded to accommodate thespinous processes. The lower portion 4231 and upper portion 4232 of thefirst wing 4230 act as a stop mechanism when the implant 4200 isinserted between adjacent spinous processes. The implant 4200 cannot beinserted beyond the surfaces of the first wing 4230. Additionally, oncethe implant 4200 is inserted, the first wing 4230 can prevent someside-to-side, or posterior-to-anterior movement of the implant 4200.

As with the implant 4100 of FIG. 48A, the implant 4200 of FIG. 48Bfurther includes a second wing 4260. Similar to the first wing 4230, thesecond wing 4260 includes a lower portion 4261 and an upper portion 4262sized and/or shaped to accommodate the anatomical form or contour of thespinous processes and/or lamina. The second wing 4260 can be secured tothe main body of the implant 4200 with a fastener 4254. The second wing4260 also has an alignment tab 4268. When the second wing 4260 isinitially placed on the main body of the implant 4200, the alignment tab4268 engages the alignment track 4203. The alignment tab 4268 slideswithin the alignment track 4203 and helps to maintain the adjustablewing 4260 substantially parallel with the first wing 4230. When the mainbody of the implant 4200 is inserted into the patient and the secondwing 4260 has been attached, displacement along the longitudinal axis4225 in either the direction of insertion or the direction oppositeinsertion can be limited or blocked.

Further, the second wing 4260 also can prevent some side-to-side, orposterior-to-anterior movement.

For both the implant 4100 of FIG. 48A and the implant 4200 of FIG. 48B,where a second wing 4160,4260 is connected with the implant 4100,4200after the implant 4100,4200 is positioned between the spinous processes,a procedure for positioning such an implant 4100,4200 and subsequentlyconnecting the second wing 4160,4260 with the implant 4100,4200 canrequire a bilateral approach wherein a physician must access both sidesof the interspinous ligament, a first side to pierce and/or distract theinterspinous ligament and position the implant 4100,4200 so that themovement in the direction of insertion is satisfactorily limited by thefirst wing 4130,4230, and a second side to attach the second wing4160,4260 such that movement in the direction opposite insertion issatisfactorily limited by the second wing 4160,4260.

Implants Having Deployable Second Wing

Referring to FIGS. 49A through 49B, implants 4300 and methods forpositioning such implants in accordance with the present invention can,in an embodiment, include a deployable second wing 4360 associated witha main body 4301 such that the second wing 4360 can be deployed with aphysician needing only to access a first side of spinous processes tolimit or block movement along the longitudinal axis 4325. As shown inFIG. 49A, the implant 4300 includes a main body 301 having a fixedspacer 4320 and a distraction guide 4310. The distraction guide 4310comprises a first winglet (also referred to herein as an upper winglet)4312 and a second winglet (also referred to herein as a lower winglet)4314, and when arranged in a first configuration can include a tip fromwhich the distraction guide 4310 expands, the tip having a diametersufficiently small such that the tip can pierce an opening in aninterspinous ligament and between spinous processes and/or can beinserted into a small initial dilated opening. The diameter and/orcross-sectional area of the distraction guide 4310 is then graduallyincreased until it is substantially similar to the diameter of thespacer 4320. In this respect, the distraction guide 4310 of FIG. 49A canresemble a distraction guide as described above when arranged in thefirst configuration. The winglets 4312,4314 can be hinged or otherwisepivotably connected with the main body 4301 such that the winglets4312,4314 can be arranged in a second configuration (FIG. 49B) once theimplant 4300 is positioned between spinous processes. In a secondconfiguration one or both of the winglets 4312,4314 abut at least one ofthe spinous processes and/or related tissues when urged in a directionopposite from insertion, thereby limiting motion along the longitudinalaxis 4325. Thus when arranged in a second configuration, the distractionguide 4310 becomes a second wing 4360, as shown in FIG. 49B.

The implant 4300 includes an insert 4370 having an insert body 4372 anda first wing 4330. As shown in FIG. 49B, the insert 4370 can be matedwith the main body 4301 to arrange the distraction guide 4310 of theimplant 4300 in the second configuration, thereby deploying the secondwing 4360. To facilitate mating of the main body 4301 and the insert4370, the spacer 4320 includes a cavity sized and shaped for receivingthe insert body 4372 and accessible from a distal end of the main body4301. A portion of the upper winglet 4312 and the lower winglet 4314 canextend at least partially into the cavity so that when the insert body4372 is received within the cavity, the insert body 4372 displaces theportions, causing the distraction guide 4310 to be arranged in thesecond configuration. In the embodiment shown, the upper winglet 4312and the lower winglet 4314 each include a lever 4316,4318 comprising acurved protrusion that protrudes into the cavity when the distractionguide 4310 is in the first configuration. As the insert body 4372 of theinsert 4370 fills the cavity, the insert body 4372 contacts the firstlever 4316 and the second lever 4318, applying a force to the firstlever 4316 and the second lever 4318 which translates into a pivotingmotion of the hinged upper winglet 4312 and the hinged lower winglet4314. The insert body 4372 can optionally have a tapered proximal end4374 having a first groove 4376 and a second groove 4378 correspondingto the first lever 4316 and the second lever 4318, respectively. Thetapered shape of the proximal end 4374 allows the upper winglet 4312 andlower winglet 4314 to be deployed gradually, fully deploying as theinsert body 4372 is fully seated within the cavity. The main body 4301is shown including a flange 4303 in which is formed notches 4305 toreceive an insertion tool (not shown), for example. As the insert body4372 is seated within the cavity, an upper tab 4332 and a lower tab 4331of the first wing 4330 seats within cut-outs 4322 of the flange 4303.

Referring to FIG. 50A, the main body 4301 of the implant 4300 is shownpositioned between adjacent spinous processes of the targeted motionsegment. The motion segment shown is within the lumbar region, but inother embodiments, particularly where a fixed spacer 4320 is used,implants 4300 in accordance with the present convention can bepositioned at motion segments of the thoracic and cervical region. Themain body 4301 is positioned as shown by initially approaching theinterspinous ligament between the upper and lower adjacent spinousprocesses 2,4 through an opening to the right of the interspinousligament, roughly posterior to the right inferior articular facet 6 ofthe vertebrae from which the upper spinous process 2 extends. The mainbody 4301 can be associated with one or more insertion tools (notshown), and the distraction guide 4310 can be arranged in the firstconfiguration. The tip of the distraction guide 4310 is positionedroughly adjacent to a point along the interspinous ligament, and thedistraction guide 4310 is then urged through the interspinous ligament,piercing the interspinous ligament and/or separating and distractingfibers of the interspinous ligaments. The main body 4301 is then urgedthrough the interspinous ligament until the spacer 4320 is positionedbetween the adjacent spinous processes 2,4 so that the spacer 4320supports a load applied by the spinous processes 2,4.

Referring to FIG. 50B, once the implant 4300 is positioned as desired,the insertion tools can be removed from the opening and the insert 4370can be positioned at the distal end of the main body 4301. The insertbody 4372 can be urged into the cavity within the main body 4301 untilthe proximal end 4374 of the insert body 4372 contacts the first lever4316 and the second lever 4318. The insert 4370 can then be furtherurged along the longitudinal axis 4325 so that the insert body 4372urges the first lever 4316 and the second lever 4318 away from theinsert body 4372, causing the upper winglet 4312 and the lower winglet4314 to pivot about the first hinge 4313 and the second hinge 4315,respectively. As the first lever 4316 and the second lever 4318 aredisplaced from the cavity, the first lever 4316 and the second lever4318 are guided along corresponding grooves 4376,4378 of the taperedproximal end 4374. As the insert body 4372 seats within the cavity ofthe main body 4301, the upper winglet 4312 and the lower winglet 4314deploy as a second wing 4360. The insertion tool can be removed from theincision once the insert body 4372 is seated within the main body 4301.As can be seen a portion of the upper spinous process and a portion ofthe lower spinous process are sandwiched between the first wing 330 andthe second wing 4360, limiting motion along the longitudinal axis 4325.Implants and methods for positioning such implants between spinousprocesses in accordance with the present invention are not meant to belimited to embodiments as described above and otherwise herein, butrather are meant to include any implant having a second wing deployableby urging an insert within a main body positioned between adjacentspinous processes. Myriad different variations maybe readily apparent toone of ordinary skill in the art. For example, in an alternativeembodiment, the main body 4301 of the implant 4300 of FIGS. 49A through50B can include a lower winglet 4314 pivotably associated with the mainbody 4301 while an upper winglet 4312 is fixedly associated with themain body 4301. An insert 4370 can be adapted to deploy only the lowerwinglet 4314 when seated within the cavity of the main body 4301.

In other embodiments, a first wing 4310 can extend from the main body4301 rather than, or in addition to, a first wing extending from theinsert 4370. When the main body 4301 is initially positioned between theadjacent spinous processes, movement of the main body 4301 along thelongitudinal axis 4325 can be limited in the direction of insertion. Asthe first wing 4310 extending from the main body 4301 contacts one orboth of the adjacent spinous processes, further movement of the mainbody 4301 in the direction of insertion can be limited or blocked. Thefirst wing 4310 can thus act as a hard stop, allowing the main body 4301to be positioned without requiring a position of the main body 4301along the spinous processes to be estimated, thereby easingimplantation.

Referring to FIG. 51, in still further embodiments implants 4400 inaccordance with the present invention can include one or both of a firstengagement element (also referred to herein as an upper hook) 4480 and asecond engagement element (also referred to herein as a lower hook) 4482for limiting flexion motion in a motion segment. For example, similarhooks have been described in greater detail in U.S. Pat. No. 6,451,019issued Sep. 17, 2002 to Zucherman et al. and U.S. Pat. No. 6,652,527issued Nov. 25, 2003 to Zucherman et al., both incorporated herein byreference. Implants in accordance with the present invention can includesuch arrangements. The implant 4400 shown in FIGS. 51 and 52 includes anupper hook 4480 extending from an upper connection rod 4484 rotatablyassociated with the main body 4401 and a lower hook 4482 extending froma lower connection rod 4486 rotatably associated with the main body4401. Alternatively, the connection rods 4484,4486 can be fixedlyassociated with the main body 4401.

The hooks 4480,4482 include tapered proximal ends 4481,4483 that act aslead-in tissue expanders to distract interspinous ligaments of themotion segments above and below the targeted motion segment. As the mainbody 4401 is positioned between adjacent spinous processes, the taperedproximal ends 4481,4483 of the upper and lower hooks 4480,4482 canlikewise pierce and/or distract interspinous ligaments so that the upperand lower hooks 4480,4482 can be properly positioned to limit orrestrain flexion motion of the targeted motion segment when the mainbody 4401 is in place. As shown, the hooks 4480,4482 can be pivotablyassociated with the connection rods 4484,4486 so that the hooks4480,4482 can be rotated relative to the connection rods 4484,4486,thereby allowing a physician to improve contact and spread loads betweenthe hooks 4480,4482 and corresponding spinous processes 2,4. Therotatable upper connection rod 4484 and lower connection rod 4486 canprovide flexibility in placement, so that where an anatomy variesbetween patients and varies between motion segments such that thearrangement of a minor dimension and major dimension of the implant44400 about the longitudinal axis 4425 varies, the implant 4400 can beaccommodated.

FIG. 52 is a posterior view of the implant 4400 positioned betweenadjacent spinous processes 2,4 and having an upper hook 4480 and a lowerhook 4482 arranged so that both flexion and extension is limited asdesired. Further, the second wing 4460 is deployed to limit movement ofthe implant 4400 along the longitudinal axis 4425. The upper hook 4480and the lower hook 4482 prevent movement along the longitudinal axis4425 in the direction opposite insertion, making a first wingunnecessary.

Referring to FIGS. 53A and 53B, in still other embodiments implants 4500and methods for positioning such implants 4500 between spinous processesin accordance with the present invention can include a distraction guide4510 wherein portions of the distraction guide 510 can be extended fromthe distraction guide 4510 to form an upper winglet 4512 and a lowerwinglet 4514, respectively, of a second wing 4560 by positioning aninsert 4570 within a cavity of the main body 4501. This is in contrastto the above embodiment where the entire distraction guide is formed bythe winglets. In this embodiment, the winglet 4512,4514 extend out theside of the distraction guide 4510. When not extended, as seen in FIG.53A, the winglet 4512,4514 partially form the sides of the distractionguide 4510. Such embodiments are contemplated to be useful where it isdesired that the second wing 4560 have a limited height relative toimplants 4300,4400 as described above where the entire distraction guide4310 is deployed (see FIG. 49A through 50B). For example, where implants4500 are to be positioned at adjacent motion segments, it can be desiredthat the second wings 4560 of the implants 4500 do not interfere withone another implant, for example during an extension motion whencompressive loads are applied to the implants 4500. As with implantsdescribed above, one of ordinary skill in the art can appreciate themyriad different variations of the implant 4500 of FIGS. 53A and 53B.For example, in alternative embodiments the upper winglet 4512 and thelower winglet 4514 can have some other shape. For example, the positionsof the upper winglet 4512 and lower winglet 4514 are staggered so thatimplants 4500 positioned at adjacent motion segments can be more easilypositioned without interfering with one another. Such staggering canalso accommodate anatomies where one of the upper and lower spinalprocesses is wider than the other. With staggering, for example, theupper winglet 4512 can be pivotably mounted on the distraction guide4510 at a position less distant from the distraction end 4511 than thelocation where the lower winglet 4514 is pivotably mounted on thedistraction guide 4510. In still other embodiments, the upper winglet4512 and the lower winglet 4514 can have some other shape. Referring toFIGS. 54A through 55, in still further embodiments of implants 4600 inaccordance with the present invention, the main body 4601 can include ahollow central body 4605 (shown in FIGS. 54C and 54D) extending from afirst wing 4630. A rotatable spacer 4620 is disposed about the hollowcentral body 4605. The implant 4600 can include a spacer 4620 thatresembles spacers, for example, as described above in FIG. 48B. Adistraction guide 4610 can extend from the hollow central body 4605 andcan include an upper winglet 4612 and a lower winglet 4614, one or bothof which can be pivotably associated with a main portion 4611 of thedistraction guide 4610 so that the upper winglet 4612 and/or the lowerwinglet 4614 can be deployed as a second wing 4660. A pin 4606 can beinserted into the hollow central body 4605 to deploy the second wing4630. Referring to FIG. 54B, once the pin 4606 is seated within the mainbody 4601, the upper winglet 4612 and the lower winglet 4614 can bepivoted away from each other so that the upper winglet 4612 and thelower winglet 4614 limit or block motion along the longitudinal axis4625 in the direction opposite from insertion. The upper winglet 4612and the lower winglet 4614 thus act as a second wing 4660.

Referring to the partial cross-sections of FIGS. 54C and 54D, in anembodiment the distraction guide 4610 can include a cup 4616 structuresized and arranged to receive the pin 4606. Bar structures 4618,4619 canbe pivotably connected between the cup structure 4616 and one or both ofthe upper winglet 4612 and the lower winglet 4614 so that when a forceis applied to the cup structure 4616 by the pin 4606, the force isfurther transferred to the upper winglet 4612 and the lower winglet4614, causing the upper winglet 4612 and the lower winglet 4614 to pivoton hinges 4613,4615 associated with the main portion 4611 of thedistraction guide 4610 so that the second wing 4660 is deployed. As canbe seen, the pivot points 4613,4615 of the upper winglet 4612 and thelower winglet 4614 are arranged proximally relative to the mount points4617,4619 of the bar structures 4618,4619, causing the upper winglet4612 and the lower winglet 4614 to pivot away from one another when themount points 4617,4619 are urged together by the insertion of the pin4606 (as seen in FIG. 54D). In other embodiments, the upper winglet 4612and the lower winglet 4614 can be caused to pivot away from one anotherusing some other mechanism. Implants in accordance with the presentinvention are not intended to be limited to such second wing deploymentmechanisms as are described in detail herein.

Referring to FIG. 55, the implant 4600 is shown positioned betweenadjacent spinous processes 2,4. The second wing 4660 as shown is sizedsuch that when arranged in a first configuration (i.e., as a distractionguide 4610) the upper winglet 4612 and the lower winglet 4614 do notextend undesirably into the adjacent tissues. However, the upper winglet4612 and the lower winglet 4614 can be sized and shaped other than asshown in FIG. 55. The upper winglet 4612 and the lower winglet 4614 needonly be sized and shaped such that when arranged in a secondconfiguration, the upper and lower winglets 4612,4614 limit or blockmovement along the longitudinal axis 4625 in a direction opposite frominsertion. FIGS. 56A through 56C illustrate a further embodiment of animplant 4700 in accordance with the present invention arranged betweenadjacent spinous processes 2,4. In such an embodiment, upper and lowerwinglets 4712,4714 can be disposed within the distraction guide 4710 andcan be deployed by actuating an actuator arrangement including a shaftconnected with a cam 4707, the shaft having an engageable head 4706, oralternatively including some other mechanism such as a gear. As can beseen in FIG. 56A the implant 4700 can be disposed between adjacentspinous processes 2,4 as described above in reference to FIG. 50. Thedistraction guide 4710 of the implant 4700 can be employed to pierceand/or distract an interspinous ligament 6 connected between theadjacent spinous process 2,4. The implant 4700 can then be urged betweenthe spinous processes 2,4 so that the distraction guide 4710 furtherdistracts the interspinous ligament 6 to form a space within which aspacer 4220 can be disposed. In the embodiment shown, the spacer 4220can pivot about a central body extending from the first wing 4230 of theimplant 4700. The first wing 4230 limits and/or blocks movement along alongitudinal axis 4725 of the implant 4700 in the direction ofinsertion.

Once the implant 4700 is arranged as desired, the actuator arrangementcan be actuated to deploy the upper and lower winglets, 4712,4714,thereby forming a second wing 4760 as shown in FIG. 56C. The second wing4760 limits and/or blocks movement along the longitudinal axis 4725 in adirection opposite the direction of insertion. With the second wing 4760deployed, the adjacent spinous processes 2,4 are at least partiallydisposed between the wings 4730,4760, preventing the implant 4800 frombecoming undesirably dislodged from the space between the adjacentspinous processes 2,4. As shown in FIG. 56C, the first wing 4730 and thesecond wing 4760 can be arranged sufficiently far apart that theadjacent spinous processes 2,4 can move relative to one another slightly(e.g., laterally—such as during a twisting motion), allowing the patientgreater flexibility of movement.

FIGS. 56B and 56C are partial cross-sectional posterior views of theimplant 4700 shown in FIG. 56A. m an embodiment, the deployable winglets4712,4714 can be extended from the distraction guide 4710 using anactuator arrangement comprising a shaft 4707 and cam 4716. The cam 4716can be rotated to force the winglets 4712,4714 to pivot outward from thedistraction guide 4710. As shown, the winglets 4712,4714 are at leastpartially disposed within a cavity of the distraction guide 4710.

FIGS. 56A through 57E illustrate a still further embodiment of animplant 4800 in accordance with the present invention arranged betweenadjacent spinous processes 2,4. In such an embodiment, upper and lowerwinglets 4812,4814 can be disposed within the distraction guide 4810 andcan be deployed by actuating an actuator arrangement including a screw4807 having an engageable head 4806, or alternatively including someother mechanism such as a gear. As can be seen in FIG. 57A the implant4800 can be disposed between adjacent spinous processes 2,4 as describedabove in reference to FIG. 50. The distraction guide 4810 of the implant4800 can be employed to pierce and/or distract an interspinous ligament6 connected between the adjacent spinous process 2,4. The implant 4800can then be urged between the spinous processes 2,4 so that thedistraction guide 4810 further distracts the interspinous ligament 6 toform a space within which a spacer 4220 can be disposed. In theembodiment shown, the spacer 4220 can pivot about a central bodyextending from the first wing 4230 of the implant 4800. The first wing4230 limits and/or blocks movement along a longitudinal axis 4825 of theimplant 4800 in the direction of insertion.

Once the implant 4800 is arranged as desired, the actuator arrangementcan be actuated to deploy the upper and lower winglets, 4812,4814,thereby forming a second wing 4860 as shown in FIG. 56B. The second wing4860 limits and/or blocks movement along the longitudinal axis 4825 in adirection opposite the direction of insertion. With the second wing 4860deployed, the adjacent spinous processes 2,4 are at least partiallydisposed between the wings 4830,4860, preventing the implant 4800 frombecoming undesirably dislodged from the space between the adjacentspinous processes 2,4. As shown in FIG. 56B, the first wing 4830 and thesecond wing 4860 can be arranged sufficiently far apart that theadjacent spinous processes 2,4 can move relative to one another slightly(e.g., laterally—such as during a twisting motion), allowing the patientgreater flexibility of movement.

FIGS. 57C and 57D are partial cross-sectional end views of the implant4800 shown in FIGS. 57A and 57B. In an embodiment, the deployablewinglets 4812,4814 can be extended from the distraction guide 4810 usingan actuator arrangement comprising a screw 4806 and threaded collar4816. The threaded collar 4816 can be driven along the screw 4806 toforce the winglets 4812,4814 to pivot outward from the distraction guide4810. As shown, the winglets 4812,4814 are at least partially disposedwithin a cavity of the distraction guide 4810. The winglets 4812,4814are pivotably connected with the threaded collar 4816 at an upper pivotpoint 4817 and a lower pivot point 4819. Pins 4813,4815 or otherobstruction devices can be disposed within the cavity and arranged sothat the pins 4813,4815 do not interfere with the arrangement of thewinglets 4812,4814 in a nested, or undeployed, position. However, as thethreaded collar 4816 travels along the screw 4806 in aposterior-to-anterior direction, the inner surface of the winglets4812,4814 contact the pins 4813,4815 and the winglets 4812,4814 pivotaway from the distraction guide 4810. If desired the winglets 4812,4814can be spring biased against the posts 4813,4815 such that in the nestedpositions and in any deployed position the winglets 4812,4814 are heldagainst the posts 4813,4815.

As shown in FIGS. 57D and 57E, when the threaded collar 4816 hastraveled a distance along the screw 4806, the winglets 4812,4814 aredeployed to form a second wing 4860. The winglets 4812,4814 extend alonga significant portion of the outer surface of the spinous processes 2,4.When urged along the longitudinal axis 4825 in a direction opposite thedirection of insertion, the winglets 4812,4814 contact the adjacentspinous processes 2,4 and resist further movement in said direction.FIG. 57E is an end view of the implant 4800 with the second wing 4860deployed. As shown, the screw head 4806 extends from the distractionguide 4810; however, when implemented, it is preferable for the screwhead 4806 to be either flush with the surface of the distraction guide4810 or slightly receded from the surface of the distraction guide 4810so that movement of the implant 4800 is not obstructed duringdistraction of the interspinous ligament 6 and/or the spinous processes2,4. The screw head 4806 is shown extending from the distraction guide4810 to demonstrate possible arrangement relative to the proximal end ofthe distraction guide 4810.

FIGS. 58A and 58B illustrate yet another embodiment of the implant 4900having an alternative actuation arrangement. In such an embodiment, thewinglets 4912,4914 can be reversed in arrangement so that the winglets4912,4914 are deployed by urging the threaded collar 4916 toward thescrew head 4806. FIGS. 59A and 59B illustrate a still further embodimentof the implant 5000 having an alternative actuation arrangement. In suchembodiments, the winglets 5012,5014 include two hinged portions, eachwinglet 5012,5014 folding outward to form a portion of a second wing5060. The second wing 5060 does not extend as far along the axis of thespine, i.e. the total height of the second wing 5060 along the spine issmaller than previous embodiments. A reduced second wing height can beadvantageous where implants are positioned at adjacent motion segments,thereby preventing undesired contact of adjacent implants.

As mentioned above, in other embodiments in accordance with the presentinvention, the winglets can be deployed from the distraction guide usinga mechanism other than a screw and threaded collar. For example, one ormore gears can be employed. Further, in still other embodiments theupper and lower winglets can have a shape along other than those shapesshown in FIGS. 57A through 57B. The invention is not intended to belimited to winglets having shapes such as shown. In still furtherembodiments, such as shown in FIG. 60, the implant 5100 can include onlyone of the upper and lower winglets. For example, where implants arepositioned at adjacent motion segments it can be advantageous to have alower winglet 4814, thereby preventing undesired contact of adjacentimplants 5100. As will be obvious to one of ordinary skill in the art,myriad different actuation arrangements can be employed to form a secondwing. Implants in accordance with the present invention are not intendedto be limited to those described in detail herein.

Materials for Use in Implants of the Present Invention

In some embodiments, the implant, and components of the implant (i.e.,the spacer, the distraction guide, etc.) can be fabricated from medicalgrade metals such as titanium, stainless steel, cobalt chrome, andalloys thereof, or other suitable implant material having similar highstrength and biocompatible properties. Additionally, the implant can beat least partially fabricated from a shape memory metal, for exampleNitinol, which is a combination of titanium and nickel. Such materialsare typically radiopaque, and appear during x-ray imaging, and othertypes of imaging. Implants in accordance with the present invention,and/or portions thereof can also be fabricated from somewhat flexibleand/or deflectable material. In these embodiments, the implant and/orportions thereof can be fabricated in whole or in part from medicalgrade biocompatible polymers, copolymers, blends, and composites ofpolymers. A copolymer is a polymer derived from more than one species ofmonomer. A polymer composite is a heterogeneous combination of two ormore materials, wherein the constituents are not miscible, and thereforeexhibit an interface between one another. A polymer blend is amacroscopically homogeneous mixture of two or more different species ofpolymer. Many polymers, copolymers, blends, and composites of polymersare radiolucent and do not appear during x-ray or other types ofimaging. Implants comprising such materials can provide a physician witha less obstructed view of the spine under imaging, than with an implantcomprising radiopaque materials entirely. However, the implant need notcomprise any radiolucent materials.

One group of biocompatible polymers is the polyaryletherketone groupwhich has several members including polyetheretherketone (PEEK), andpolyetherketoneketone (PEKK). PEEK is proven as a durable material forimplants, and meets the criterion of biocompatibility. Medical gradePEEK is available from Victrex Corporation of Lancashire, Great Britainunder the product name PEEK-OPTIMA. Medical grade PEKK is available fromOxford Performance Materials under the name OXPEKK, and also fromCoorsTek under the name BioPEKK. These medical grade materials are alsoavailable as reinforced polymer resins, such reinforced resinsdisplaying even greater material strength. In an embodiment, the implantcan be fabricated from PEEK 450G, which is an unfilled PEEK approved formedical implantation available from Victrex. Other sources of thismaterial include Gharda located in Panoli, India. PEEK 450G has thefollowing approximate properties:

Property Value Density 1.3 g/cc Rockwell M 99 Rockwell R 126 TensileStrength 97 MPa Modulus of Elasticity 3.5 GPa Flexural Modulus 4.1 GPa

PEEK 450G has appropriate physical and mechanical properties and issuitable for carrying and spreading a physical load between the adjacentspinous processes. The implant and/or portions thereof can be formed byextrusion, injection, compression molding and/or machining techniques.It should be noted that the material selected can also be filled.Fillers can be added to a polymer, copolymer, polymer blend, or polymercomposite to reinforce a polymeric material. Fillers are added to modifyproperties such as mechanical, optical, and thermal properties. Forexample, carbon fibers can be added to reinforce polymers mechanicallyto enhance strength for certain uses, such as for load bearing devices.In some embodiments, other grades of PEEK are available and contemplatedfor use in implants in accordance with the present invention, such as30% glass-filled or 30% carbon-filled grades, provided such materialsare cleared for use in implantable devices by the FDA, or otherregulatory body. Glass-filled PEEK reduces the expansion rate andincreases the flexural modulus of PEEK relative to unfilled PEEK. Theresulting product is known to be ideal for improved strength, stiffness,or stability. Carbon-filled PEEK is known to have enhanced compressivestrength and stiffness, and a lower expansion rate relative to unfilledPEEK. Carbon-filled PEEK also offers wear resistance and load carryingcapability.

As will be appreciated, other suitable similarly biocompatiblethermoplastic or thermoplastic polycondensate materials that resistfatigue, have good memory, are flexible, and/or deflectable, have verylow moisture absorption, and good wear and/or abrasion resistance, canbe used without departing from the scope of the invention. As mentioned,the implant can be comprised of polyetherketoneketone (PEKK). Othermaterial that can be used include polyetherketone (PEK),polyetherketoneetherketoneketone (PEKEKK), polyetheretherketoneketone(PEEKK)5 and generally a polyaryletheretherketone. Further, otherpolyketones can be used as well as other thermoplastics. Reference toappropriate polymers that can be used in the implant can be made to thefollowing documents, all of which are incorporated herein by reference.These documents include: PCT Publication WO 02/02158 A1, dated Jan. 10,2002, entitled “Bio-Compatible Polymeric Materials;” PCT Publication WO02/00275 A1, dated Jan. 3, 2002, entitled “Bio-Compatible PolymericMaterials;” and, PCT Publication WO 02/00270 A13 dated Jan. 3, 2002,entitled “Bio-Compatible Polymeric Materials.” Other materials such asBionate®, polycarbonate urethane, available from the Polymer TechnologyGroup, Berkeley, Calif., may also be appropriate because of the goodoxidative stability, biocompatibility, mechanical strength and abrasionresistance. Other thermoplastic materials and other high molecularweight polymers can be used.

Methods for Implanting Interspinous Implants

A minimally invasive surgical method for implanting an implant 4300 asshown in FIGS. 49A-55 in the cervical spine is disclosed and taughtherein. In this method, as shown in FIG. 61, preferably a guide wire4780 is inserted through a placement network 4790 into the neck of theimplant recipient. The guide wire 4780 is used to locate where theimplant 4300 is to be placed relative to the cervical spine, includingthe spinous processes. Once the guide wire 4780 is positioned with theaid of imaging techniques, an incision is made on the side of the neckso that an implant 4300 in accordance with an embodiment of the presentinvention, can be positioned in the neck thorough an incision and alonga line that is about perpendicular to the guide wire 4780 and directedat the end of the guide wire 4780. The main body 4301 of the implant4300 is inserted into the neck of the patient. Preferably duringinsertion, the distraction guide 4310 pierces or separates the tissuewithout severing the tissue. Once the main body 4301 is satisfactorilypositioned, an insert 4370 can be positioned within a cavity of the mainbody 4301, causing the distraction guide 4310 of the main body 4301 tobe arranged in a second configuration so that at least a portion of thedistraction guide 4310 forms a second wing. The insert 4370 can beinserted along a line that is generally collinear with the line overwhich the main body 4301 is inserted. The anatomy of the neck is suchthat it is most convenient and minimally invasive to enter the neck fromthe side with respect to the main body 4301 and the insert 4370.

Further, a minimally invasive surgical method for implanting an implantas described in FIGS. 49A-55 in the lumbar spine is disclosed and taughtherein. In this method, as shown in the flowchart of FIG. 62, preferablya unilateral incision or opening can be made using a posterior-anteriorapproach (Step 2802). The unilateral incision can be made, for example,at a location some distance to the left of an axis along the spinousprocess. The incision or opening can be enlarged, and a distraction toolcan be positioned within the incision so that the proximal end of thedistraction tool (Step 2804) can access an exposed side of theinterspinous ligament. The distraction tool can be urged through theinterspinous ligament, thereby distracting the interspinous ligament soas to receive the implant (Step 2806). Once the interspinous ligament issufficiently distracted, the distraction tool can be disengaged andremoved from the incision (Step 2808).

Once the distraction tool has been removed from the incision, theimplant can be positioned at the dilated opening, and the distractionguide of the implant can be urged through the dilated opening (Step2810). The implant can be further urged through the opening until thespacer is positioned as desired between the adjacent spinous processesof the targeted motion segment (Step 2812). The spacer is free to rotateso that the load is distributed more evenly over the surface of thespinous processes. Optionally, the implant can be urged through thedilated opening until the first wing contacts the adjacent spinousprocesses, thereby blocking further movement in the direction ofinsertion. Once the implant is properly arranged, the insert can bepositioned at the distal end of the implant so that the insert can beurged into and through the hollow cavity of the hollow central body(Step 2814). As the insert is seated inside of the cavity, thedistraction guide splits, and the upper winglet and the lower wingletdeploy as a second wing. The remaining tools can be removed from theincision, and the incision can be closed (Step 2816). Preferably duringinsertion, the distraction end pierces or separates the tissue withoutsevering the tissue. Further, a minimally invasive surgical method forimplanting an implant as shown in FIGS. 56A-60 in the lumbar spine isdisclosed and taught herein. In this method, as shown in the flowchartof FIG. 63, an incision or opening can be made using aposterior-anterior approach (Step 2852). The incision or opening can beenlarged, and a distraction tool can be positioned within the incisionso that the proximal end of the distraction tool (Step 2854) can accessan exposed side of the interspinous ligament. The distraction guide canbe urged through the interspinous ligament and distracted, therebydistracting the interspinous ligament so as to receive the implant (Step2856). Once the interspinous ligament is sufficiently distracted, thedistraction tool can be disengaged and removed from the incision (Step2858).

Once the distraction guide has been removed from the incision, theimplant can be positioned at the dilated opening, and the distractionguide of the implant can be urged through the dilated opening (Step2860). The implant can be further urged through the opening until thespacer is positioned as desired between the adjacent spinous processesof the targeted motion segment (Step 2862). The spacer is free to rotateso that the load is distributed more evenly over the surface of thespinous processes. Optionally, the implant can be urged through thedilated opening until the first wing contacts the adjacent spinousprocesses, thereby blocking further movement in the direction ofinsertion. Once the implant is properly arranged, an actuation tool canbe inserted within the incision at an opposite side of the adjacentspinous processes from the point of insertion (Step 2864). The actuationtool can engage the actuation arrangement, and can actuate the actuationarrangement so that the upper winglet and the lower winglet deploy as asecond wing, as described above (Step 2866). The remaining tools can beremoved from the incision, and the incision can be closed (Step 2868).Preferably during insertion, the distraction end pierces or separatesthe tissue without severing the tissue.

The foregoing description of the present invention have been presentedfor purposes of illustration and description. It is not intended to beexhaustive or to limit the invention to the precise forms disclosed.Many modifications and variations will be apparent to practitionersskilled in this art. The embodiments were chosen and described in orderto best explain the principles of the invention and its practicalapplication, thereby enabling others skilled in the art to understandthe invention for various embodiments and with various modifications asare suited to the particular use contemplated. It is intended that thescope of the invention be defined by the following claims and theirequivalents.

Implants Having Deployable Wings

In other embodiments, implants in accordance with the present inventioncan comprise a “matchbox”-like structure having a first configuration(as shown in FIG. 64A) and a second, deployed configuration (as shown inFIG. 64B). Arranged in the first configuration, such implants 6700 canhave a substantially flat profile having an approximately uniformthickness.

The uniform thickness approximates the thickness of a spacer 6720 of theimplant 6700. The implant 6700 can comprise a distraction guide 6710 ata proximal end of the implant, the distraction guide 6710 having aslightly rounded or tapered shape to pierce and/or distract a spacebetween adjacent spinous processes. The implant 6700 can furthercomprise a plurality of hinged structures 6750-6757, the hingedstructures 6750-6757 being collapsed so as to facilitate thesubstantially flat profile. The hinged structures 6750-6757 arepivotally connected with the spacer 6720 and extend from both sides ofthe spacer 6720. As shown in FIG. 64A, a support structure 6722 extendsfrom the spacer 6720 toward the distal end of the implant 6700. A rod6715 (or alternatively some other mechanism such as a tab) can beconnected with the proximal end of the implant 6700 and can extendthrough the hinged structures 6750-6753, through the spacer 66720, andthrough the support structure 6722 so that the rod 6715 is accessible.

Referring to FIG. 64B, once the implant 6700 is positioned as desiredbetween adjacent spinous processes, the rod 6715 can be drawn in adirection opposite the direction of insertion along the longitudinalaxis 6725 so that the hinged structures 6750-6757 fold outward to form afirst wing 6730 and a second wing 6760 between which is arranged thespacer 6720 and a portion of the spinous processes. As the hingedstructures 6750-6757 fold outward, the height of the first and secondwings 6730,6760 increases from approximately the same as the thicknessof the spacer 6720 to a height such that the first and second wing6730,6760 can limit or block movement of the implant 6700 along thelongitudinal axis 6725 when positioned between adjacent spinousprocesses. As can be seen, the second wing 6760 includes four hingedstructures 6750-6753: an upper first structure 6750 connected by a hingeto an upper second structure 6752, and a lower first structure 6751connected by a hinge to a lower second structure 6753. The hingedstructures 6750-6753 pivot outward to form an upper end 6762 of thesecond wing and a lower end 6764 of the second wing. Likewise, the firstwing 6730 includes four hinged structures 6754-6757: an upper firststructure 6754 connected by a hinge to an upper second structure 6756,and a lower first structure 6755 connected by a hinge to a lower secondstructure 6757. However, unlike the second wing 6760, the first wing6730 is (effectively) bisected by the support structure 6722 so that thefirst wing 6730 comprises four winglets 6731-6734. The hinged structures6754-6757 pivot outward to form upper winglets 6731,6732 of the firstwing and lower winglets 6733,6734 of the first wing.

As mentioned above, the support structure 6722 extends from the spacer6720 toward the distal end of the implant 6700. The spacer 6720 and thesupport structure 6722 include a bore or other cavity through which therod 6715 can travel. Applying resistive force to the support structure6722 can fix the spacer 6720 in place between spinous processes whendrawing the rod 6715 through the bore. As the rod 6715 is drawn throughthe bore, the hinged structures 6752,6753 with which the proximal end ofthe rod 6715 is connected are drawn with the rod 6715. As the rod 6715is drawn through the spacer 6720, the hinged structures 6752,6753 aredrawn toward the spacer 6720. The hinged structures 6750-6753 pivotoutward to accommodate the relative movement between the rod 6715 andthe spacer 66720. Accordingly, the second wing 6760 has beensatisfactorily deployed.

The hinged structures 6756,6757 of the first wing 6730 can causedeployment of the first wing 6730 by applying resistive force to thehinged structures 6756,6757 while drawing the spacer 6720 (via thesupport structure 6722), or by urging the hinged structures 6756,6757toward the spacer 6720. The resistive force or urging can be applied bya second stop 6784 that can fit around the support structure 6722 andcan be interference fit or otherwise selectively fixed with the supportstructure 6722. As the second stop 6784 is pushed along the longitudinalaxis 6725, along the support structure 6722, the hinged structures6754-6757 pivot outward to accommodate the relative movement between thesecond stop 6784 and the spacer 6720. Accordingly, the first wing 6730has been satisfactorily deployed.

FIGS. 65A and 65B are posterior views of the implant 6700 positionedbetween adjacent spinous processes 2,4 demonstrating an embodiment of amethod for deploying the implant 6700 between the spinous processes 2,4.The implant 6700 can be positioned so that a distraction guide 6710 ofthe implant 6700 is arranged at a space between the spinous processes2,4. The implant 6700 can then be urged between the spinous processes2,4 so that the spacer 6720 is positioned as desired. The substantiallyflat profile of the implant 6700 can ease positioning of the spacer 6720by reducing potential obstructing surfaces that can resist movement ofthe implant 6700 during implantation. The second wing 6760 and the firstwing 6730 can then be deployed to limit movement of the implant 6700. Todeploy the second wing 6760 the rod 6715 is drawn in a directionopposite the direction of insertion along the longitudinal axis 6725.The upper end 6762 and lower end 6764 of the second wing extend outwardas described above. Once the second wing 6760 is deployed, the rod 6715can be fixed in position relative to the spacer 6720. This can beaccomplished using myriad different mechanisms. For example, as shown afirst stop 6782 can be interference fit to the rod 6715 and positionedagainst the support structure 6722 along the rod 6715. The first stop6782 can grip the rod 6715, as with a friction fit between the firststop 6782 and the rod 6715, so that the rod 6715 is prevented frommoving through the bore of the support structure 6722 by interferencebetween the first stop 6782 and the support structure 6722. In otherembodiments, some other mechanism can be used, such as a pin (e.g., acotter pin), a latch system, etc. One of ordinary skill in the art willappreciate the myriad different mechanisms for fixing a rod 6715 inposition relative to the spacer 6720. The upper second structure 6756and the lower second structure 6757 can be urged toward the spacer 6720in the direction of insertion along the longitudinal axis 6725 using asecond stop 6784 as described above, causing the upper winglets6731,6732 and lower winglets 6733,6734 to extend outward to form thefirst wing 6730. Once the first wing 6730 is deployed, the hingedstructures 6754-6757 can be fixed in position using the second stop 6784or some other mechanism. The second stop 6784 can grip the supportstructure 6722, as with a friction fit or pin, and resist movement ofthe hinged structures 6754-6757, thereby preventing collapse. As above,one of ordinary skill in the art will appreciate the myriad differentmechanisms for fixing the first wing 6730 in a deployed position. Withthe first wing 6730 and the second wing 6760 deployed, movement of theimplant 6700 along the longitudinal axis 6725 can be limited or blocked,thereby resisting undesirable displacement of the implant 6700.

It should be noted that with implants as described above in reference toFIGS. 64A-67 the rod 6715 can optionally be trimmed or otherwisepartially detached to decrease a space required to accommodate theimplant 6700,6800 within the patient's spine. For example, the structureof the rod 6715 can be beveled or otherwise weakened near a distal endof the rod 6715 to allow the rod 6715 to be snapped off when the firstand second wings 6730,6760,6830,6860 are deployed and the rod 6715 isfixed in place. In other embodiments, a tool (not shown) can be used tocut the rod 6715 after the first and second wings 6730,6760,6830,6860are deployed and the rod 6715 is fixed in place. Still further, the rod6715 need not comprise a rigid structure, but rather alternatively caninclude a tether, string, or similarly flexible structure that can beplaced in tension to retain the second wing 6760,6860 and/or first wing6730,6830 in a deployed position.

Referring to FIGS. 66A and 66B, a still further embodiment of an implant6800 in accordance with the present invention is shown. In such anembodiment, a flexible strap 6890 can be connected between pairs ofhinged structures (i.e., 6850 and 6852, 6851 and 6853, 6854 and 6856,6855 and 6857). The flexible strap 6890 can limit the relative movementof the hinged structures 6850-6857 so that first wing 6830 and secondwing 6860 have increased rigidity when fully deployed. The implant 6800need not include the support structure 6722 of the previous embodiment.A resistive force can be applied to the hinged structures 6856,6857 sothat as the rod 6715 is drawn in a direction opposite the direction ofinsertion along the longitudinal axis 6825 the resistive force causesthe hinged structures 6854-6857 to extend outward to form the first wing6830. As the hinged structures 6854-6857 extend outward the flexiblestrap 6890 connected opposite the hinge unfolds. Once the hingedstructures 6854-6857 reach a maximum extension, the flexible strap 6890becomes taut and resists further extension, locking the first wing 6830in place. The flexible straps 6890 can provide the first wing 6830 withsufficient rigidity to resist movement of the spacer 6720, so that asthe rod 6715 is further drawn the rod 6715 moves through the spacer 6720and the hinged structures 6852,6853 connected with the rod 6715 aredrawn toward the spacer 6720. As the hinged structures 6852,6853connected with the rod 6715 are drawn toward the spacer 6720, all of thehinged structures 6850-6853 extend outward to deploy the second wing6860. The flexible strap 6890, connected opposite the hinge, unfolds.Once the hinged structures 6854-6857 reach a maximum extension theflexible strap 6890 becomes taut and resists further extension, lockingthe first wing 6830 in place. A stop 6882 (or alternatively some othermechanism such as a pin) can be fixed to the rod 6715 to createinterference between the stop 6882 and the hinged structures 6832,6834of the first wing 6830 that resists movement of the rod 6715. Theflexible straps 6890 can be made from a biocompatible material. In anembodiment, the flexible straps 6890 can be made from a braidedpolyester suture material. Braided polyester suture materials include,for example, Ethibond, Ethiflex, Mersilene, and Dacron, and arenon-absorbable, having high tensile strength, low tissue reactivity andimproved handling. In other embodiments, the flexible straps 6890 can bemade from stainless steel (i.e., surgical steel), which can be woveninto a strap, for example. In still other embodiments, flexible straps6890 can be made from some other material (or combination of materials)having similar properties.

FIG. 67 is a posterior view of the implant 6800 positioned betweenadjacent spinous processes 2,4 demonstrating an embodiment of a methodfor deploying the implant 6800 between the spinous processes 2,4. Thefirst wing 6830 can be deployed to limit movement of the implant 6800relative to the spinous processes 2,4. To deploy the first wing 6830 therod 6715 can be held fixed in position or urged in a direction oppositethe direction of insertion along the longitudinal axis 6825 while aforce is applied to the hinged structures 6854-6857 (FIG. 66A) of thefirst wing 6830 to cause the upper end 6832 of the first wing and thelower end 6834 of the first wing to extend away from the rod 6715,thereby deploying the first wing 6830. The rod 6715 can be further urgedin the direction opposite the direction of insertion so that theproximal end of the rod 6715 pivotably connected with the hingedstructures 6852,6853 that comprise the distraction guide 6710, is drawntoward the spacer 6720, causing the upper end 6862 of the spacer, andthe lower end 6864 of the spacer to extend away from the rod 6715. Oncethe second wing 6860 and the first wing 6830 are deployed, the rod 6715can be fixed in position relative to the spacer 6720. As above, this canbe accomplished using myriad different mechanisms. For example, as showna first stop 6882 can be interference fit to the rod 6715 and positionedagainst the first wing 6830 along the rod 6715. The first stop 6882 cangrip the rod 6715 so that the rod 6715 is prevented from moving by afriction fit between the first stop 6882 and the rod 6715. In otherembodiments, some other mechanism can be used, such as a pin (e.g., acotter pin), a latch system, etc. One of ordinary skill in the art willappreciate the myriad different mechanisms for fixing a rod 6715 inposition relative to the spacer 6720. With the first wing 6830 and thesecond wing 6860 deployed, movement of the implant 6800 along thelongitudinal axis 6825 can be limited or blocked, thereby resistingundesirable displacement of the implant 6800.

Referring to FIGS. 68A and 68B, in still other embodiments, implants inaccordance with the present invention can comprise a “matchbox”-likestructure having a rounded, collapsed first configuration and a second,deployed configuration. Arranged in the first configuration, suchimplants 6900 can have a shape allowing the implant 6900 to be morenaturally inserted through a cannula. As shown, such a shape includes asubstantially circular cross-section, though in other embodiments theimplant can have an ovoid or elliptical cross-section, thereby allowinga spacer shape to be employed that generally accommodates a spacebetween adjacent spinous processes. However, it will be appreciated thatan implant 6900 having a circular cross-section can most efficiently usethe space of a cannula, where the cannula includes a circularcross-section; therefore, it may be preferable to employ an implant 6900having a circular cross-section where a physician desired to minify thediameter of the cannula inserted into the surgical site.

The cross-section of the implant 6900 in a first configuration isgenerally consistent along the implant's length, having a diametergenerally the thickness of a spacer 6920 of the implant 6900. Theimplant 6900 can comprise a distraction guide 6910 at a proximal end ofthe implant 6900, the distraction guide 6910 having a rounded (as shown)or tapered shape to pierce and/or distract a space between adjacentspinous processes. However, where a cannula is employed to deliver animplant to a surgical site, the implant 6900 can optionally include adistraction guide 6910 at the proximal end. The surgical site, andassociated tissues and structures can be distracted and repositioned bythe cannula, allowing substantially unobstructed access to the surgicalsite by the implant 6900. In such circumstance a distraction guide 6910may not be necessary.

The implant 6900 can further comprise a plurality of hinged structures6950-6957, the hinged structures 6950-6957 being collapsed so as tofacilitate the substantially collapsed profile. The hinged structures6950-6957 are pivotally connected with the spacer 6920 and extend fromboth sides of the spacer 6920. A rod 6915 (or alternatively some othermechanism such as a tab) can be connected with the proximal end of theimplant 900 and can extend through the hinged structures 6950-6953, andthrough the spacer 6920 so that the rod 6915 is accessible to aphysician. Referring to FIGS. 68B and 68C, once the implant 6900 ispositioned as desired between adjacent spinous processes, the rod 6915can be drawn in a direction opposite the direction of insertion alongthe longitudinal axis 6925 so that the hinged structures 6950-6957 foldoutward to form a first wing 6930 and a second wing 6960 between whichis arranged the spacer 6920 and a portion of the spinous processes. Asthe hinged structures 6950-6957 fold outward, the height of the firstand second wings 6930,6960 increases from approximately the same as thethickness of the spacer 6920 to a height such that the first and secondwing 6930,6960 can limit or block movement of the implant 6900 along thelongitudinal axis 6925 when positioned between adjacent spinousprocesses. As can be seen, the second wing 6960 includes four hingedstructures 6950-6953: an upper first structure 6950 connected by a hingeto an upper second structure 6952, and a lower first structure 6951connected by a hinge to a lower second structure 6953. The hingedstructures 6950-6953 pivot outward to form an upper end 6962 of thesecond wing and a lower end 6964 of the second wing. Likewise, the firstwing 6930 includes four hinged structures 6954-6957: an upper firststructure 6954 connected by a hinge to an upper second structure 6956,and a lower first structure 6955 connected by a hinge to a lower secondstructure 6957.

Embodiments as described above in reference to FIGS. 64A and 64Bincluded a support structure 6722 extending from the spacer 6720.Likewise, a support structure can optionally extend from the spacer 6920of the cannula delivered implant 6900. However, such a structure neednot be necessary where the first wing 6930 is prevented from deployingduring deployment of the second wing 6960 by the cannula 6995 itself(see FIG. 69B). Referring to FIGS. 69A and 69B, once the cannula ispositioned at the surgical site, the implant 6900 can be urged throughthe cannula so that the hinged structures 6950-6953 are clear of thecannula. The rod 6915 can then be urged in an opposite direction(relative to insertion) along the longitudinal axis 6925 to deploy thesecond wing 6960. As the rod 6915 is drawn through the spacer 6920, thehinged structures 6952,6953 are drawn toward the spacer 6920. The hingedstructures 6950-6953 pivot outward to accommodate the relative movementbetween the rod 6915 and the spacer 6920. Accordingly, the second wing6960 has been satisfactorily deployed.

Once the second wing 6960 is deployed, the cannula 6995 can be retractedfrom the surgical site, thereby allowing the hinged structures 6956,6957of the first wing 6930 to deploy by urging the hinged structures6956,6957 toward the spacer 6920. The urging can be applied by a stop6982 that can fit around the rod 6915 and can be interference fit orotherwise selectively fixed with the rod 6915. As the stop 6982 ispushed along the longitudinal axis 6925, along the rod 6915, the hingedstructures 6954-6957 pivot outward to accommodate the relative movementbetween the stop 6982 and the spacer 6920. Accordingly, the first wing6930 has been satisfactorily deployed.

Once the second wing 6960 and the first wing 6930 are deployed, the rod6915 can be fixed in position relative to the spacer 6920. As above,this can be accomplished using myriad different mechanisms. For example,as shown a stop 6982 can be interference fit to the rod 6915 andpositioned against the first wing 6930 along the rod 6915. The stop 6982can grip the rod 6915 so that the rod 6915 is prevented from moving by afriction fit between the stop 6982 and the rod 6915. In otherembodiments, some other mechanism can be used, such as a pin (e.g., acotter pin), a latch system, etc. One of ordinary skill in the art willappreciate the myriad different mechanisms for fixing a rod 6915 inposition relative to the spacer 6920. With the first wing 6930 and thesecond wing 6960 deployed, movement of the implant 6900 along thelongitudinal axis 6925 can be limited or blocked, thereby resistingundesirable displacement of the implant 6900.

It should be noted that with implants as described above in reference toFIGS. 68A-69B the rod 6915 can optionally be trimmed or otherwisepartially detached to decrease a space required to accommodate theimplant 6900 within the patient's spine. For example, the structure ofthe rod 6915 can be beveled or otherwise weakened near a distal end ofthe rod 6915 to allow the rod 6915 to be snapped off when the first andsecond wings 6930,6960 are deployed and the rod 6915 is fixed in place.In other embodiments, a tool (not shown) can be used to cut the rod 6915after the first and second wings 6930,6960 are deployed and the rod 6915is fixed in place. Still further, the rod 6915 need not comprise a rigidstructure, but rather alternatively can include a tether, string, orsimilarly flexible structure that can be placed in tension to retain thesecond wing 6960 and/or first wing 6930 in a deployed position.

Referring to FIGS. 68B, 68C and 69B, the implant 6900 is shown havingoperably connected “hinged” structures 6950-6957. Such structures can behinged in any way that permits relative movement. For example, thestructures may be hinged by way of flexible straps, for example asdescribed above in reference to FIG. 66B. Alternatively, the structurescan be hinged using some other technique. For example, referring to FIG.70C, one or a pair of cords 6996 can connect pairs of hinged structuresso that relative movement is restricted, thereby permitting hingingmotion, while resisting separation of the structures. In still otherembodiments, some other mechanism can be employed to define a range ofmovement of the hinged structures 6950-6957. One of ordinary skill inthe art will appreciate the myriad different techniques for defining arange of motion of two mechanical parts.

As with the flexible straps 6890 above, the cord 6996 can be made from abiocompatible material. In an embodiment, the cord 996 can be made froma braided polyester suture material. Braided polyester suture materialsinclude, for example, Ethibond, Ethiflex, Mersilene, and Dacron, and arenon-absorbable, having high tensile strength, low tissue reactivity andimproved handling. In other embodiments, the cords 6996 can be made fromstainless steel (i.e., surgical steel), which can be woven into a strap,for example. In still other embodiments, the cords 6996 can be made fromsome other material (or combination of materials) having similarproperties.

Materials for Use in Implants of the Present Invention

In some embodiments, the implant can be fabricated from medical grademetals such as titanium, stainless steel, cobalt chrome, and alloysthereof, or other suitable implant material having similar high strengthand biocompatible properties. Additionally, the implant can be at leastpartially fabricated from a shape memory metal, for example Nitinol,which is a combination of titanium and nickel. Such materials aretypically radiopaque, and appear during x-ray imaging, and other typesof imaging. Implants in accordance with the present invention, and/orportions thereof can also be fabricated from somewhat flexible and/ordeflectable material. In these embodiments, the implant and/or portionsthereof can be fabricated in whole or in part from medical gradebiocompatible polymers, copolymers, blends, and composites of polymers.A copolymer is a polymer derived from more than one species of monomer.A polymer composite is a heterogeneous combination of two or morematerials, wherein the constituents are not miscible, and thereforeexhibit an interface between one another. A polymer blend is amacroscopically homogeneous mixture of two or more different species ofpolymer. Many polymers, copolymers, blends, and composites of polymersare radiolucent and do not appear during x-ray or other types ofimaging. Implants comprising such materials can provide a physician witha less obstructed view of the spine under imaging, than with an implantcomprising radiopaque materials entirely. However, the implant need notcomprise any radiolucent materials.

One group of biocompatible polymers are the polyaryl ester ketones whichhas several members including polyetheretherketone (PEEK), andpolyetherketoneketone (PEKK). PEEK is proven as a durable material forimplants, and meets the criterion of biocompatibility. Medical gradePEEK is available from Victrex Corporation of Lancashire, Great Britainunder the product name PEEK-OPTIMA. Medical grade PEKK is available fromOxford Performance Materials under the name OXPEKK, and also fromCoorsTek under the name BioPEKK. These medical grade materials are alsoavailable as reinforced polymer resins, such reinforced resinsdisplaying even greater material strength. In an embodiment, the implantcan be fabricated from PEEK 450G, which is an unfilled PEEK approved formedical implantation available from Victrex. Other sources of thismaterial include Gharda located in Panoli, India. PEEK 450G has thefollowing approximate properties:

Property Value Density 1.3 g/cc Rockwell M 99 Rockwell R 126 TensileStrength 97 MPa Modulus of Elasticity 3.5 GPa Flexural Modulus 4.1 GPa

PEEK 450G has appropriate physical and mechanical properties and issuitable for carrying and spreading a physical load between the adjacentspinous processes. The implant and/or portions thereof can be formed byextrusion, injection, compression molding and/or machining techniques.

It should be noted that the material selected can also be filled.Fillers can be added to a polymer, copolymer, polymer blend, or polymercomposite to reinforce a polymeric material. Fillers are added to modifyproperties such as mechanical, optical, and thermal properties. Forexample, carbon fibers can be added to reinforce polymers mechanicallyto enhance strength for certain uses, such as for load bearing devices.In some embodiments, other grades of PEEK are available and contemplatedfor use in implants in accordance with the present invention, such as30% glass-filled or 30% carbon-filled grades, provided such materialsare cleared for use in implantable devices by the FDA, or otherregulatory body. Glass-filled PEEK reduces the expansion rate andincreases the flexural modulus of PEEK relative to unfilled PEEK. Theresulting product is known to be ideal for improved strength, stiffness,or stability. Carbon-filled PEEK is known to have enhanced compressivestrength and stiffness, and a lower expansion rate relative to unfilledPEEK. Carbon-filled PEEK also offers wear resistance and load carryingcapability.

As will be appreciated, other suitable similarly biocompatiblethermoplastic or thermoplastic polycondensate materials that resistfatigue, have good memory, are flexible, and/or deflectable, have verylow moisture absorption, and good wear and/or abrasion resistance, canbe used without departing from the scope of the invention. As mentioned,the implant can be comprised of polyetherketoneketone (PEKK). Othermaterial that can be used include polyetherketone (PEK),polyetherketoneetherketoneketone (PEKEKK), polyetheretherketoneketone(PEEKK), and generally a polyaryletheretherketone. Further, otherpolyketones can be used as well as other thermoplastics. Reference toappropriate polymers that can be used in the implant can be made to thefollowing documents, all of which are incorporated herein by reference.These documents include: PCT Publication WO 02/0215S A1, dated Jan. 10,2002, entitled “Bio-Compatible Polymeric Materials;” PCT Publication WO02/00275 A1, dated Jan. 3, 2002, entitled “Bio-Compatible PolymericMaterials;” and, PCT Publication WO 02/00270 A1, dated Jan. 3, 2002,entitled “Bio-Compatible Polymeric Materials.” Other materials such asBionate®, polycarbonate urethane, available from the Polymer TechnologyGroup, Berkeley, Calif., may also be appropriate because of the goodoxidative stability, biocompatibility, mechanical strength and abrasionresistance. Other thermoplastic materials and other high molecularweight polymers can be used.

As described above, the binder can be made from a biocompatiblematerial. In an embodiment, the binder can be made from a braidedpolyester suture material. Braided polyester suture materials include,for example, Ethibond, Ethiflex, Mersilene, and Dacron, and arenonabsorbable, having high tensile strength, low tissue reactivity andimproved handling. In other embodiments, the binder can be made fromstainless steel (i.e., surgical steel), which can be braided into atether or woven into a strap, for example. In still other embodiments,the binder can be made from some other material (or combination ofmaterials) having similar properties. It is to be understood thatembodiments in accordance with the present invention can be constructedwithout a pliant material. It is also to be understood that theembodiments in accordance with the present invention can have otherdimensions.

Methods for Implanting Interspinous Implants

A minimally invasive surgical method for implanting an implant 6400 inthe cervical spine is disclosed and taught herein. In this method, asshown in FIG. 70, preferably a guide wire 80 is inserted through aplacement network or guide 90 into the neck of the implant recipient.The guide wire 80 is used to locate where the implant is to be placedrelative to the cervical spine, including the spinous processes. Oncethe guide wire 80 is positioned with the aid of imaging techniques, anincision is made on the side of the neck so that an implant inaccordance with an embodiment of the present invention, can bepositioned in the neck thorough an incision and along a line that isabout perpendicular to the guide wire 80 and directed at the end of theguide wire 80. In one embodiment, the implant can be a sized implant 400(i.e., having a body that is not distractible), such as described abovein FIGS. 7-23 and including a distraction guide 6410, a spacer 6420, anda first wing 6430. The implant 6400 is inserted into the neck of thepatient. Preferably during insertion, the distraction guide 6410 piercesor separates the tissue without severing the tissue.

Once the implant 6400 is satisfactorily positioned, a second wing 6460can be optionally inserted along a line that is generally collinear withthe line over which the implant 6400 is inserted but from the oppositeside of the neck. The anatomy of the neck is such that it is mostconvenient and minimally invasive to enter the neck from the side withrespect to the implant 6400 and the second wing 6460. The second wing6460 is mated to the implant and in this particular embodiment, thesecond wing 6460 is attached to the implant 6400 by the use of afastener, for example by a screw 6442. Where a screw is used, the screw6442 can be positioned using a screw driving mechanism that is directedalong a posterior to anterior line somewhat parallel to the guide wire80. This posterior to anterior line aids the physician in viewing andsecuring the second wing 6460 to the implant. The second wing 6460 ispositioned so that a bore 6463 formed in a lip 6461 of the second wing6460 is aligned with a bore 6440 of the implant 6400, as describedabove. The screw 6442 is positioned within both bores and secured, atleast, to the bore 6440 of the implant 6400. In other embodiments, thesecond wing can be interference fit with the implant, as describedabove, or fastened using some other mechanism, such as a flexible hingeand protrusion.

A minimally invasive surgical method for implanting an alternativeembodiment of an implant 6700 in the cervical spine is disclosed andtaught herein. In this method, as shown in FIG. 25, preferably a guidewire 80 is inserted through a placement network or guide 90 into theneck of the implant recipient. The guide wire 80 is used to locate wherethe implant 6700 is to be placed relative to the cervical spine,including the spinous processes. Once the guide wire 80 is positionedwith the aid of imaging techniques, an incision is made on the side ofthe neck so that an implant 700 in accordance with an embodiment of thepresent invention, can be positioned in the neck thorough an incisionand along a line that is about perpendicular to the guide wire 80 anddirected at the end of the guide wire 80. In an embodiment, the implant6700 can include a distraction guide 6710, a spacer 6720, a rod 6715extending through the spacer 6720, and deployable first and second wings6730,6760. The implant 6700 can have a substantially flat profile toease implantation, as described above. The implant 6700 is inserted intothe neck of the patient. Preferably during insertion, the distractionguide 6710 pierces or separates the tissue without severing the tissue.

Once the implant 6700 is satisfactorily positioned, the first wing 6730and the second wing 6760 can be deployed. As described above, the secondwing 6760 can be deployed by urging the rod 6715 in a direction oppositethe direction of insertion along the longitudinal axis 6725. As the rod6715 travels through the spacer 6720, hinged structures 6750-6753contact the spacer 66720, buckle and extend away from the rod 6715 twoform an upper end 6762 of the second wing and a lower end 6764 of thesecond wing. When second wing 6760 is satisfactorily deployed, the rod6715 can be fixed in place relative to the spacer 6720 using a firststop 6782, a pin, or some other mechanism. The first wing 6730 can bedeployed by urging the hinged structures 6754-6757 toward the spacer6720, causing the hinged structures 6754-6757 to buckle and extend awayfrom one another to form an upper end 6732 of the second wing and alower end 6734 of the second wing. The anatomy of the neck is such thatit is most convenient and minimally invasive to enter the neck from theside with respect to the implant 6700. A minimally invasive surgicalmethod for implanting an alternative embodiment of an implant 6900 inthe cervical spine is disclosed and taught herein. In this method, asshown in FIG. 72, preferably a guide wire 80 is inserted through aplacement network or guide 90 into the neck of the implant recipient.The guide wire 80 is used to locate where the implant 6900 is to beplaced relative to the cervical spine, including the spinous processes.Once the guide wire 80 is positioned with the aid of imaging techniques,an incision is made on the side of the neck along a line that is aboutperpendicular to the guide wire 80 and directed at the end of the guidewire 80. The cannula 6995 is fed through the incision and positionedbetween the targeted adjacent spinous processes. In an embodiment, theimplant 6900 can include a distraction guide 6910, a spacer 6920, a rod6915 extending through the spacer 6920, and deployable first and secondwings 6930,6960. The implant 6900 can have a substantially circularcross-section to roughly conform with an inside surface of the cannula6995. The implant 6900 is urged through the cannula 6995 and intoposition between the adjacent spinous processes so that the second wing6960 hinge structures are clear of the cannula 6995, as described abovein reference to FIG. 68B. The second wing 6960 is then deployed byurging the rod 6915 in a direction opposite the direction of insertionalong the longitudinal axis 6925. As the rod 6915 travels through thespacer 6920, hinged structures 6950-6953 contact the spacer 6920, buckleand extend away from the rod 6915 two form an upper end 6962 of thesecond wing and a lower end 6964 of the second wing. When second wing6960 is satisfactorily deployed, the cannula 6995 can be retracted toexpose the hinged structures 6954-6957 of the first wing 6930. The firstwing 6930 can be deployed by urging the hinged structures 6954-6957toward the spacer 6920, causing the hinged structures 6954-6957 tobuckle and extend away from one another to form an upper end 6932 of thesecond wing and a lower end 6934 of the second wing. Once the first wing6930 is deployed, the rod 6915 can optionally be shortened, and thecannula 6995 can be withdrawn from the incision. The incision can thenbe closed.

The foregoing description of the present invention have been presentedfor purposes of illustration and description. It is not intended to beexhaustive or to limit the invention to the precise forms disclosed.Many modifications and variations will be apparent to practitionersskilled in this art. The embodiments were chosen and described in orderto best explain the principles of the invention and its practicalapplication, thereby enabling others skilled in the art to understandthe invention for various embodiments and with various modifications asare suited to the particular use contemplated. It is intended that thescope of the invention be defined by the following claims and theirequivalents.

Interspinous Implants

FIG. 73A is a perspective view of an implant as described in U.S. patentapplication Ser. No. 10/850,267, filed May 20, 2004, incorporated hereinby reference. The implant 7100 comprises a first wing 7130, a spacer7120, and a lead-in tissue expander (also referred to herein as adistraction guide) 7110. The distraction guide 7110 in this particularembodiment is wedge-shaped, i.e., the implant has an expandingcross-section from a proximal end of the implant 7100 to a region 7150where the guide 7110 joins with the spacer 7120 (referencing for thefigures is based on the point of insertion of the implant betweenspinous processes). As such, the distraction guide 7110 functions toinitiate distraction of the soft tissue and the spinous processes whenthe implant 7100 is surgically inserted between the spinous processes.It is to be understood that the distraction guide 7110 can be pointedand the like, in order to facilitate insertion of the implant 7100between the spinous processes of adjacent cervical vertebrae. It isadvantageous that the insertion technique disturb as little of the boneand surrounding tissue or ligaments as possible in order to reducetrauma to the site and promote early healing, and preventdestabilization of the normal anatomy. For embodiments such as those ofFIGS. 73A and 73B, there is no requirement to remove any of the bone ofthe spinous processes and no requirement to sever, or remove from thebody, ligaments and tissues immediately associated with the spinousprocesses. For example, it is unnecessary to sever the supraspinalligament of the lower vertebrae or the ligamentum nuchae (whichcorresponds to the supraspinal ligament) which partially cushions thespinous processes of the upper cervical vertebrae. As can be seen, thespacer 7120 can be teardrop-shaped in cross-section perpendicular to alongitudinal axis 7125 of the implant 7100. In this way, the shape ofthe spacer 7120 can roughly conform to a wedge-shaped space, or aportion of the space, between adjacent spinous processes within whichthe implant 7100 is to be positioned. As shown in FIG. 1A, the spacer7120 (and the first wing 7108) is shaped to accommodate the anatomicalform or contour of spinous processes (and/or laminae) of the C6 and C7vertebra for placement between such spinous processes (i.e., the C6-C7motion segment). The same shape or variations of this shape can be usedto accommodate other motion segments, for example in the thoracic orlumbar regions. In other embodiments the spacer 7120 can havealternative shapes such as circular, wedge, oval, ovoid, football, andrectangular with rounded corners, and other shapes. The shape of thespacer 7120 can be selected for a particular patient so that thephysician can position the implant 7100 as close as possible to theanterior portion of the surface of the spinous process. The shapeselected for the spacer 7120 can affect the contact surface area of theimplant 7100 and the spinous processes that are to be subject todistraction. Increasing the contact surface area between the implant7100 and the spinous processes can distribute a load force between thespinous frame and the implant 7100. The first wing 7130 is likewiseteardrop-shaped in cross-section perpendicular to a longitudinal axis7125 of the spacer 7120 and distraction guide 7110. The dimensions ofthe first wing 7130 can be larger than that of the spacer 7120,particularly along the axis of the spine, and can limit or block lateraldisplacement of the implant 7100 in the direction of insertion along thelongitudinal axis 7125. As with the spacer 7120, the first wing 7130 canhave other cross-sectional shapes, such as elliptical, wedge, circular,oval, ovoid, football, and rectangular with rounded corners and othershapes.

The implant 7100 of FIG. 73A further includes an adjustable wing 7160(also referred to herein as a second wing) separate from the distractionguide 7110, the spacer 7120 and the first wing 7130. The second wing7160 is connectable with the distraction guide 7110 (and/or the spacer7120) once the implant 7100 is positioned between adjacent spinousprocesses. The second wing 7160, similar to the first wing 7130, canlimit or block lateral displacement of the implant 7100, howeverdisplacement is limited or blocked in the direction opposite insertion.When both the first wing 7130 and the second wing 7160 are connectedwith the implant 7100 and the implant 7100 is positioned betweenadjacent spinous processes, a portion of the spinous processes can besandwiched between the first wing 7130 and the second wing 7160,limiting displacement along the longitudinal axis 7125. As can be seen,the second wing 7160 can be teardrop-shaped in cross-section. A lip 7180defining a space 7170 through the second wing 7160 allows the secondwing 7160 to pass over the distraction guide 7110 to meet and connectwith the distraction guide 7110 and/or the spacer 7120. The second wing7160 is then secured to the distraction guide 7110 and/or the spacer7120. The second wing 7160, can be designed to be interference-fit ontothe spacer 7120 or a portion of the distraction guide 7110 adjacent tothe spacer 7120. Where the second wing 7160 is interference-fit, thereis no additional attachment device to fasten the second wing 7160relative to the remainder of the implant 7100.

Alternatively, various fasteners can be used to secure the second wing7160 relative to the remainder of the implant 7100. For example, FIG.73A illustrates an embodiment of an implant 7100 including ateardrop-shaped second wing 7160 having a tongue 7158 at the posteriorend of the second wing 7160. A bore 7155 is disposed through the tongue7158, and is aligned with a corresponding bore 7156 on the spacer 7120when the second wing 7160 is brought into position by surgical insertionrelative to the rest of the implant 7100. A threaded screw 7154 can beinserted through the aligned bores 7155,7156 in a posterior-anteriordirection to secure the second wing 7160 to the spacer 7120. Thedirection of insertion from a posterior to an anterior direction has thescrew 7154 engaging the bores 7155,7156 and the rest of the implant 7100along a direction that is generally perpendicular to the longitudinalaxis 7125. This orientation is most convenient when the physician isrequired to use a screw 7154 to secure the second wing 7160 to the restof the implant 7100. The second wing 7160 can further be secured to thespacer 7120 by some other mechanism, for example such as a flexiblehinge (not shown) with a protrusion that engages an indentation of oneof the distraction guide 7110 and the spacer 7120. Alternatively, thesecond wing 7160 can be secured to one of the distraction guide 7110 andthe spacer 7120 by still some other mechanism.

FIG. 73B is a perspective view of an implant as described in U.S. Pat.No. 6,695,842 to Zucherman, et al, incorporated herein by reference. Theimplant 7200 has a main body that includes a spacer 7220, a first wing7230, a lead-in tissue expander 7210 (also referred to herein as adistraction guide) and an alignment track 7203. The main body of theimplant 7200 is inserted between adjacent spinous processes and remainsin place (where desired) without attachment to the bone or ligaments.

The distraction guide 7210 includes a tip from which the distractionguide 7210 expands, the tip having a diameter sufficiently small suchthat the tip can pierce an opening in an interspinous ligament and/orcan be inserted into a small initial dilated opening. The diameterand/or cross-sectional area of the distraction guide 7210 graduallyincreases until it is substantially similar to the diameter of thespacer 7220. The tapered front end eases the ability of a physician tourge the implant 7200 between adjacent spinous processes. When urgingthe main body of the implant 7200 between adjacent spinous processes,the front end of the distraction guide 7210 distracts the adjacentspinous processes and dilates the interspinous ligament so that a spacebetween the adjacent spinous processes is approximately the diameter ofthe spacer 7220.

As shown in FIG. 73B, the spacer 7220 is elliptically shaped incross-section, and can swivel so that the spacer 7220 can self-alignrelative to the uneven surfaces of the spinous processes. Self-alignmentcan ensure that compressive loads are distributed across the surface ofthe bone. As contemplated in Zucherman '842, the spacer 7220 can have,for example, a diameter of six millimeters, eight millimeters, tenmillimeters, twelve millimeters and fourteen millimeters. Thesediameters refer to the height by which the spacer 7220 distracts andmaintains apart the spinous process. For an elliptically shaped spacer7220, the selected height (i.e., diameter) is the minor dimensionmeasurement across the ellipse. The major dimension is transverse to thealignment of the spinous process, one above the other.

The first wing 7230 has a lower portion 7231 and an upper portion 7232.The upper portion 7232 is shaped to accommodate the anatomical form orcontour of spinous processes (and/or laminae) of the L4 (for an L4-L5placement) or L5 (for an L5-S1 placement) vertebra. The same shape orvariations of this shape can be used to accommodate other motionsegments, such as motion segments in the cervical and thoracic regions.The lower portion 7231 can also be rounded to accommodate the spinousprocesses. The lower portion 7231 and upper portion 7232 of the firstwing 7230 act as a stop mechanism when the implant 7200 is insertedbetween adjacent spinous processes. The implant 7200 cannot be insertedbeyond the surfaces of the first wing 7230. Additionally, once theimplant 7200 is inserted, the first wing 7230 can prevent someside-to-side, or posterior-to-anterior movement of the implant 7200. Aswith the implant 7100 of FIG. 73A, the implant 7200 of FIG. 73B furtherincludes a second wing 7260. Similar to the first wing 7230, the secondwing 7260 includes a lower portion 7261 and an upper portion 7262 sizedand/or shaped to accommodate the anatomical form or contour of thespinous processes and/or lamina. The second wing 7260 can be secured tothe main body of the implant 7200 with a fastener 7254. The second wing7260 also has an alignment tab 7268. When the second wing 7260 isinitially placed on the main body of the implant 7200, the alignment tab7268 engages the alignment track 7203. The alignment tab 7268 slideswithin the alignment track 7203 and helps to maintain the adjustablewing 7260 substantially parallel with the first wing 7230. When the mainbody of the implant 7200 is inserted into the patient and the secondwing 7260 has been attached, displacement along the longitudinal axis7225 in either the direction of insertion or the direction oppositeinsertion can be limited or blocked.

Further, the second wing 7260 also can prevent some side-to-side, orposterior-to-anterior movement.

For both the implant 7100 of FIG. 73A and the implant 7200 of FIG. 73B,where a second wing 7160,7260 is connected with the implant 7100,7200after the implant 7100,7200 is positioned between the spinous processes,a procedure for positioning such an implant 7100,7200 and subsequentlyconnecting the second wing 7160,7260 with the implant 7100,7200 canrequire a bilateral approach wherein a physician must access both sidesof the interspinous ligament, a first side to pierce and/or distract theinterspinous ligament and position the implant 7100,7200 so that themovement in the direction of insertion is satisfactorily limited by thefirst wing 7130,7230, and a second side to attach the second wing7160,7260 such that movement in the direction opposite insertion issatisfactorily limited by the second wing 7160,7260.

Implants having a Lead-In Screw

Referring to FIGS. 74A through 75C, implants 7300 and methods forpositioning such implants in accordance with the present invention caninclude, in an embodiment, a frame 7302 having a central body 7304extending along a longitudinal axis 7325 of the implant 7300. Thecentral body 7304 can include a distraction guide 7306 at a proximal endof the central body 7304. The distraction guide 7306 can have a taperedshape so that the distraction guide 7306 can pierce and/or distract aninterspinous ligament associated with the targeted motion segment. Afirst wing 7330 extends from a distal end of the central body 7304 andacts to limit or block movement of the implant 7300 along thelongitudinal axis 7325 in the direction of insertion.

A substantially thread-shaped lead-in screw (also referred to herein asa second wing) 7360 extends from the periphery of the central body 7304distally located relative to the distraction guide 7306. For example,the second wing can be helical shaped, wherein a helical shape isgenerally a three-dimensional curve that lies on a cylinder or a cone,so that its angle to a plane perpendicular to the axis is constant.Helical shapes as described herein need not lie along a constant angle,but rather can lie along an angle that varies. A helical shape need onlyinclude a curve that has a gap 7361 (also referred to herein as agroove) between overlapping surfaces such that structures related to theadjacent spinous processes and the spinous processes can pass within thegroove 7361. It is to be understood that a lead-in screw shape otherthan helical is within the spirit and scope of the invention. Forexample, a shape with a constant diameter thread, or with different orconstant thread pitches can be used. Generally and preferably the secondwing 7360 can have an outer diameter that steadily increases from nearthe proximal end of the central body 7304 distally toward the first wing7330. The second wing 7360 terminates so that a spacer 7320 (FIG. 74B)can be arranged between the second wing 7360 and the first wing 7330.The helical shape of the second wing 7360 can facilitate implantationbetween adjacent spinous processes 2,4 (shown in FIGS. 75A-75E) from oneor more incisions formed on one side of an interspinous ligament 6extending between the adjacent spinous processes 2,4.

Implantation can be accomplished in such embodiments as described aboveby initially piercing or distracting the interspinous ligament 6 withthe distraction guide 7306, and subsequently rotating the central body7304. One or both of the interspinous ligament 6 and the adjacentspinous processes 2,4 slip within the groove 7361 of the helicallyshaped second wing 7360 as the central body 7304 is rotated and thecentral body 7304 is drawn or urged along the longitudinal axis 7325 inthe direction of insertion. The interspinous ligament 6 and/orassociated spinous processes 2,4 travels along the groove 7361 andtherefore along the central body 7304, causing the second wing 7360 tobe positioned, when the implant 7300 is seated, at an opposite side ofthe interspinous ligament 6 from the first wing 7330 such that theinterspinous ligament 6 is disposed between the first wing 7330 and thesecond wing 7360 along the longitudinal axis 7325. Arranging theinterspinous ligament 6, and/or the associated spinous processes 2,4between the first wing 7330 and the second wing 7360 limits or blocksmovement along the longitudinal axis 7325. In some embodiments, thedistraction guide 7306 can have a generally conical shape, rather than awedge-shape as described above in reference to FIGS. 73A and 73B. Wherethe distraction guide 7306 includes a wedge-shape, rotation of thecentral body 7304 can cause the distraction guide 7306 to distract theadjacent spinous processes 2,4 and/or interspinous ligament 6 a distanceaccording to the major dimension of the distraction guide 7306.Referring to FIG. 74A, as with the distraction guide 7306, the firstwing 7330 has a rounded shape, having substantially the same minor andmajor dimension. The first wing 7330 is shaped so that the first wing7330 can rotate along with the central body 7304 while minifyinginterference from surrounding structures. Further, the rounded shape ofthe first wing 7330 can accommodate slots as described below, whileproviding a surface to contact the adjacent spinous processes 2,4 duringimplantation, thereby limiting movement along the longitudinal axis 7325in the direction of insertion. However, in other embodiments, the firstwing 7330 need not have a rounded shape.

The first wing 7330 can include one or more slots to receive a spacer7320 so that the spacer 7320 can be arranged over the central body 7304between the second wing 7360 and the first wing 7330. As shown, thefirst wing 7330 includes two slots 7332,7334 having a substantiallyarced shape, and arranged in opposition to one another. The maximumdistance between the peripheries of the slots 7332,7334 cansubstantially define a minor (or alternatively a major) dimension of thespacer 7320. The slots 7332,7334 preferably have inner surfaces thattransition to the outer surface of the central body 7304, so that when aspacer 7320 is urged through the slots 7332,7334, the spacer 7320 abutsthe central body 7304, thereby allowing a portion of a load to betransferred to the central body 7304. In other embodiments, one or moreslots can be disposed through the first wing 7330 and can be shaped asdesired, such that the one or more slots having the same or differentgeometries.

FIG. 74B is a perspective view of the spacer 7320 having a geometryadapted to be received over the frame 7302 described above. The spacer7320 includes a top portion 7322 and a bottom portion 7324. (It shouldbe noted that some components of the implant are referred to herein as“top” and “bottom” components; however, positional modifiers areattached merely to distinguish between similar components and are notmeant to limit use of the invention.) The top portion 7322 and thebottom portion 7324 have outer surfaces that support a respectiveadjacent spinous process 2,4 and inner surfaces that abut the centralbody 7304. As shown, a portion of the inner surfaces of the top portion7322 and the bottom portion 7324 are grooved so as to approximatelyconform with a shape of the central body 7304, thereby spreading a loadacross the outer surface of the central body 7304. The outer surfacesare arced, and generally shaped to resemble the outer periphery of theslots 7332,7334 of the first wing 7330. In other embodiments, forexample where the central body is trapezoidal, or otherwise shaped, thetop portion 7322, bottom portion 7324, and corresponding slots 7332,7334can be similarly shaped to accommodate the central body 7304.Alternatively, the central body 7304 can have an irregular ornon-symmetrical shape to prevent incorrect mating of the spacer 7320with the frame 7302. One of ordinary skill in the art will appreciatethe myriad variations with which the structures can be shaped.

As can be seen, the top portion 7322 and the bottom portion 7324 includerespective lead-in tissue expanders 7321,7323 (also referred to hereinas a distraction guides). The distraction guide 7321,7323 for the topportion 7322 and the bottom portion 7324 can taper at the proximal endof the spacer 7320, thereby allowing the distraction guide 7306 todistract one or both of the adjacent spinous processes 2,4 and/orinterspinous ligament 6.

As can be seen, the top portion 7322 and the bottom portion 7324, takentogether in cross-section perpendicular to a longitudinal axis 7325, canhave a split teardrop shape, similar to a cross-section of the spacer7120 of FIG. 73A. In this way, the shape of the spacer 7320 can roughlyconform to a wedge-shaped space, or a portion of the space, betweenadjacent spinous processes within which the implant 7300 is to bepositioned. The same shape or variations of this shape can be used toaccommodate different motion segments and/or different patients, asdescribed above. In other embodiments the spacer 7320 can havealternative shapes such as circular, elliptical, wedge, oval, ovoid,football, and rectangular with rounded corners, and other shapes. Theshape of the spacer 7320 can be selected for a particular patient sothat the physician can position the implant 7300 as close as possible tothe anterior portion of the surface of the spinous process. The shapeselected for the spacer 7320 can affect the contact surface area of theimplant 7300 and the spinous processes that are to be subject todistraction. Increasing the contact surface area between the implant7300 and the spinous processes can distribute a load force between thespinous frame and the implant 7300.

The top portion 7322 and the bottom portion 7324 extend from a base 7326and are fixed in relative position by the base 7326. As can be seen, thebottom portion 7324 extends farther than the top portion 7322. As willbe described in further detail below, the top portion 7322 is truncatedin length along the longitudinal axis 7325 relative to the bottomportion 7324 to avoid contacting the second wing 7360 which in theembodiment shown in FIG. 74A spirals to a termination point at the uppersurface of the central body 7304. An additional advantage with thetruncated top portion 7322 is that the spinous processes are distractedmore gradually, first with the bottom portion 7324 and then with the topportion 7322 as the spacer 7320 is inserted into the frame 7302. Thebase 7326 can have a length along the longitudinal axis 7325 as desired,and preferably having a length sufficient to support the top portion7322 and the bottom portion 7324 in an at least semi-rigid positionrelative to one another. The base 7326 can include a cavity 7329 forreceiving one or both of an insertion tool and a fastener (not shown).The cavity 7329 can correspond to a threaded cavity 7309 disposed in thecentral body 7304 so that, for example, the frame 7302 and the spacer7320 can be fixedly attached, with by way of example only a screw, oncethe spacer 7320 is seated.

FIG. 74C is a perspective view of the implant 7300 wherein the spacer7320 is seated within the frame 7302 and arranged over the central body7304. As can be seen, the bottom portion 7324 of the spacer 7320 extendsfurther than the top portion 7322, and is unobstructed by the secondwing 7360, which spirals partially above the bottom portion 7324. Thefirst wing 7330 and the second wing 7360 have major dimensionsapproximately along the axis of the spine that are larger than the majordimension of the spacer 7320, thereby blocking or limiting movement ofthe implant 7300 along the longitudinal axis 7325.

FIGS. 75A through 75E are partial cross-sectional posterior viewsillustrating the implant 7300 being positioned between adjacent spinousprocesses. FIG. 75A illustrates the distraction guide of the frame 7302positioned adjacent to the interspinous ligament 6 of the targetedmotion segment. The frame 7302 can be urged against the interspinousligament 6 to pierce and/or distract the interspinous ligament 6. Theframe 7302 can further be urged into the interspinous ligament 6 alongthe longitudinal axis 7325 until the second wing 7360 contacts theinterspinous ligament 6. Referring to FIG. 75B, the frame 7302 can thenbe rotated and urged toward the interspinous ligament 6 so that thesecond wing 7360 passes through the interspinous ligament 6, which isthereby positioned between a portion of the second wing 7360 and thefirst wing 7330 along the longitudinal axis 7325. The interspinousligament 6 and the adjacent spinous processes 2,4 are substantiallydisposed within a groove 7361 between the surfaces of the second wing7360 that overlap along the longitudinal axis 7325. Referring to FIG.75C, the frame 7302 can be further rotated and urged into theinterspinous ligament 6 until the entire second wing 7360 issubstantially arranged so that the interspinous ligament 6 is disposedbetween the first wing 7330 and the second wing 7360. The frame 7302 canbe further rotated so that the slots 7332,7334 are arranged to receivethe spacer 7320 such that a load applied to the spacer 7320 issufficiently distributed across the surface of the spacer 7320 (i.e.,the spacer 7320 approximately conforms to a space between the contactsurfaces of adjacent spinous processes 2,4 of the targeted motionsegment). Referring to FIGS. 75D and 75E, once the frame 7304 isarranged as desired, the top portion 7322 and the bottom portion 7324can be positioned within the corresponding slots 7332,7334 and urgedover the central body 7304 so that the top portion 7322 and bottomportion 7324 further distract the interspinous ligament 6 and/or theadjacent spinous processes 2,4. The spacer 7320 can be urged in thedirection of insertion until the base 7326 is seated against the firstwing 7330. In a preferred embodiment, the top portion 7322 and thebottom portion 7324 can be arranged so that the top portion 7322 andbottom portion 7324 are approximately in contact or near-contact withthe second wing 7360, so that the spacer 7320 fully supports a loadapplied by the adjacent spinous processes 2,4, without slippage.

FIG. 76A is an end view of the implant 7300 positioned between theadjacent spinous processes 2,4 of the targeted motion segment. As can beseen, the base 7326 is arranged at a slight angle relative to the axisof the spine. As can be seen, the upper spinous process 2 includes alower contact surface that arcs slightly downward, and the lower spinousprocess 4 includes an upper contact surface that also arcs slightlydownward. Arranging the implant 7300 as shown can increase the overallcontact surface between the adjacent spinous processes 2,4 and thespacer 7320 over, for example, inserting the implant 7300 so that thebase 7326 is aligned perpendicular to the axis of the spine. Increasingoverall contact surface can reduce the stress applied from the motionsegment to the spacer 7320, and from the spacer to the adjacent spinousprocesses 2,4.

As can further be seen, the base 7326 can include a cavity 7329 that inan embodiment is a bore having a diameter larger than a diameter of acorresponding cavity 7309 of the first wing 7330. Such a feature can bereceive an insertion tool (not shown) for assisting in implantation, orsuch a feature can receive a fastener (not shown), such as a screw orbolt to secure the spacer 7320 to the frame 7302. A bore 7329 having alarger diameter than the cavity 7309 of the frame 7302 can allow a headof the fastener to be received so that the head does not extend beyond adistal face of the base 7326. In other embodiments, the base 7326 caninclude one or more additional cavities for receiving lock pins, orother features of an insertion tool (not shown), for example asdescribed in U.S. Pat. No. 6,712,819, entitled “Mating InsertionInstruments for Spinal Implants and Methods of Use,” issued Mar. 30,2004 to Zucherman, et al.

FIG. 76B is a front view of the implant 7300 positioned between theadjacent spinous processes 2,4 of the targeted motion segment. As can beseen, the second wing 7360 is helical in shape and can limit or blockmotion in a direction opposite insertion by contacting the upper spinousprocess 2.

Further, a portion of the second wing 7360 can contact the lower spinousprocess 4. Although the second wing 7360 as shown includes a helicalshape somewhat similar to that of a conch shell, in other embodimentsthe second wing 7360 can have a shape that varies from the shape shown.For example, the distal end of the second wing 7360 can overlap theproximal end of the second wing 7360 more or less than as shown.Alternatively, the second wing 7360 can be formed in two or more brokensections, rather than an unbroken spiral. Still further, the second wing7360 can include slots for receiving a proximal piece of the upper andlower portions 7322,7324 of the spacer 7320. Myriad different variationsof the shape shown in FIGS. 75A-76B will be readily apparent to one ofskill in the art upon understanding the structure shown. Implants inaccordance with the present invention are not intended to be limited tothose described and shown herein, but rather apply to all such implantsthat utilize a wing having a major dimension larger than a majordimension of a space between spinous processes, wherein the wing can beappropriately positioned by rotating the implant while urging theimplant in a direction of insertion.

Referring now to FIGS. 77A through 77C, an alternative embodiment of animplant 7400 in accordance with an embodiment of the present inventionis shown. FIG. 77A is a perspective view of the frame 7402 including acentral body 7404 having a distraction guide 7406 at a proximal end, andan alignment protrusion 7408 at a distal end. As can be seen, the secondwing 7460 is similar to the second wing 7460 described above. Thealignment protrusion 7408 extends from the central body 7404 to align aspacer 7420 as the spacer 7420 is arranged over the central body 7404,and to prevent the spacer 7420 from subsequently rotating relative tothe frame 7402 once implanted. Thus, the alignment protrusion 7408corresponds to a notch 7427 within the spacer 7420 within which thecentral body 7404 is partially disposed.

FIG. 77B is a perspective view of the spacer 7420. The spacer 7420includes a bore 7428 disposed at least partially through the spacer7420, and including a notch 7427 along the length of the bore 7428 toreceive the alignment protrusion 7408 of the frame 7402. The proximalend of the spacer 7420 can be tapered to form a distraction guide 7426to distract the interspinous ligament 6 and/or the adjacent spinousprocesses 2,4 of the motion segment. Similarly to the rotatable spacer7220 of FIG. 73B, and the implant 7300 of FIGS. 74A-74C, the implant7400 can be further rotated or adjusted to distribute a load once thespacer 7420 is positioned over the frame 7404 and between the spinousprocesses 2,4. As above, the spacer 7420 can have a cross-sectionperpendicular to the longitudinal axis 7425 that is teardrop-shaped,similar to a cross-section of the spacer 7120,7320 of FIGS. 73A and 74A.In this way, the shape of the spacer 7420 can roughly conform to awedge-shaped space, or a portion of the space, between adjacent spinousprocesses 2,4 within which the implant 7400 is to be positioned. Thesame shape or variations of this shape can be used to accommodatedifferent motion segments and/or different patients, as described above.In other embodiments the spacer 7420 can have alternative shapes such ascircular, elliptical, wedge, oval, ovoid, football, and rectangular withrounded corners, and other shapes. The shape of the spacer 7420 can beselected for a particular patient so that the physician can position theimplant 7400 as close as possible to the anterior portion of the surfaceof the spinous process 2,4. The shape selected for the spacer 7420 canaffect the contact surface area of the implant 7400 and the spinousprocesses 2,4 that are to be subject to distraction. Increasing thecontact surface area between the implant 7400 and the spinous processes2,4 can distribute a load force between the spinous frame and theimplant 7400.

The spacer 7420 of FIG. 77B extends from a first wing 7430 integrallyformed or connected with the spacer 7420. As can be seen, a proximal endof the spacer 7420 varies in length, extending farther near the bottomsection of the spacer 7420 to correspond roughly with the helical shapeof the second wing 7460, thereby avoiding contacting the second wing7460 which in the embodiment shown in FIG. 77A spirals to a terminationpoint at the upper surface of the central body 7404. As above, once theframe 7404 is arranged as desired, the spacer 7420 can be positionedover the central body 404 and urged over the central body 7404 so thatthe spacer 7420 further distracts the interspinous ligament and/or theadjacent spinous processes. The spacer 7320 can be urged in thedirection of insertion until the central body 7404 is seated within thebore 7428. In a preferred embodiment, the shape of the proximal end ofthe spacer 7420 is shaped such that when seated, the proximal end isapproximately in contact or near-contact with the second wing 7460, sothat the spacer 7420 fully supports a load applied by the adjacentspinous processes, without slippage.

The first wing 7430 can have a depth along the longitudinal axis 7425 asdesired, and a width such that the first wing 7430 can contact one orboth of the adjacent spinous processes 2,4, thereby limiting or blockingmoving of the implant 7400 in the direction of insertion along thelongitudinal axis 7425. As shown, the first wing 7430 has a roundedshape, having substantially the same minor and major dimension. Unlikethe embodiment of the implant 7300 of FIGS. 74A-74C, the first wing 7430need not rotate to properly arrange the second wing 7460, therefore thefirst wing 7430 need not have a round shape, where it is desired thatthe second wing 7460 have some other shape. For example, the first wing7430 can include a shape similar to that shown in FIG. 73B. The firstwing 7430 can include a cavity 7429 for receiving one or both of aninsertion tool (not shown). Further, the central body 7404 canoptionally include a cavity 7409 so that, for example, the frame 7402,the spacer 7420, and the first wing 7430 can be fixedly attached oncethe spacer 7420 is seated.

FIG. 77C is a perspective view of the implant 7400 wherein the spacer7420 is positioned to be seated on the frame 7402 and arranged over thecentral body 7404. The first wing 7430 and the second wing 7460 havemajor dimensions approximately along the axis of the spine that arelarger than the major dimension of the spacer 7420, thereby blocking orlimiting movement of the implant 7400 along the longitudinal axis 7425.FIG. 78 is a posterior view of an implant 7400 as described in FIGS.77A-77C disposed between the adjacent spinous processes.

In some embodiments of systems including implants 7300,7400 similar tothose shown in FIGS. 74A-77C, multiple different spacers 7320,7420 canbe selectively associated with a single frame 7302,7402 so that aphysician can choose an appropriately sized and shaped spacer 7320,7420to accommodate a patient's anatomy. In embodiments including a centralbody 7304 extending from a first wing 7330, the distance between theouter peripheries of the two slots 7332,7334 can correspond to a maximumspacer size (e.g., 14 mm). In embodiments including a central body 7404having an alignment protrusion 7408, a series of spacer 7420 can havevarying dimensions and/or shapes, and can have similarly sized cavities7428 to receive the central body 7404. As can be readily understood fromthis description, a system in accordance with embodiments of the presentinvention can include a frame 7302,7402 and a plurality of spacers7320,7420 having varying sizes and/or shapes.

As mentioned above, implants, and systems and methods for positioningsuch implants between spinous processes in accordance with the presentinvention are not meant to be limited to embodiments as described aboveand otherwise herein, but rather are meant to include all such implantsthat utilize a wing having a major dimension larger than a majordimension of a space between spinous processes, wherein the wing can beappropriately positioned by rotating the implant while urging theimplant in a direction of insertion. Myriad different variations may bereadily apparent to one of ordinary skill in the art. For example, asshown in FIGS. 79A through 79C, in still another embodiment of animplant 7500 in accordance with the present invention, the frame 7502can include an inner central body 7504 disposed within an outer centralbody 7505, with a proximal portion of a second wing 7560 being connectedwith, or extending from the inner central body 7504, and the distalportion of the second wing 7560 being connected with, or extending fromthe outer central body 7505. Once the frame 7502 is arranged as desired,such that the interspinous ligament is disposed between a first wing7330 and the second wing 7560, the inner central body 7504 can beshifted to a position more fully received in the outer central body 7505so that the second wing 7560 collapses, reducing the space occupied bythe second wing 7560.

In such embodiments as shown in FIGS. 79A through 79C, the second wing7560 can be made from a more ductile material so that the second wing7560 can be readily collapsed. Alternatively, the second wing 7560 canbe made from a shape memory material, for example such as Nitinol, sothat once the frame is positioned the second wing 7560 collapses, urgingthe inner central body 7504 to shift within the outer central body 7505.Additionally the second wing 7560 can be made in two parts, one partfastened to the inner central body 7504, and one part fastened to theouter central body 7505. When the inner central body 7504 is more fullyreceived into the outer central body 7505, the portion of the secondwing 7560 secure to the inner central body 7504 becomes nested in theportion of the second wing 7560 connected to the outer central body7505.

As shown in FIG. 80, in a still further embodiment an implant 7600 inaccordance with the present invention can include a distraction guide7606 that tapers more gradually, so that the adjacent spinous processesand/or related tissues are distracted as the lead-in screw 7660 isrotated and urged toward a direction of insertion, as described above.

In still further embodiments, the spacer need not be fixed, but rathercan be rotatably disposed over the central body. For example, the spacercan include an alignment notch, as described above with reference toFIG. 73B, so that when the central body is rotated, thereby threadingthe adjacent spinous processes and related structures within the grooveof the thread-shaped wing and positioning the thread-shaped wing on anopposite side of the adjacent spinous processes, the spacer can be heldin a fixed positioned. By fixing the spacer is position, the spacer canbe arranged as desired between the adjacent spinous processes. Once theimplant is positioned between adjacent spinous processes, the rotatablespacer can be released to conform within the space between spinousprocesses. These and other variations are within the scope of theinvention as contemplated.

Materials for Use in Implants of the Present Invention

In some embodiments, the implant, and components of the implant (i.e.,the spacer, the frame) can be fabricated from medical grade metals suchas titanium, stainless steel, cobalt chrome, and alloys thereof, orother suitable implant material having similar high strength andbiocompatible properties. Additionally, the implant can be at leastpartially fabricated from a shape memory metal, for example Nitinol,which is a combination of titanium and nickel. Such materials aretypically radiopaque, and appear during x-ray imaging, and other typesof imaging. Implants in accordance with the present invention, and/orportions thereof can also be fabricated from somewhat flexible and/ordeflectable material. In these embodiments, the implant and/or portionsthereof can be fabricated in whole or in part from medical gradebiocompatible polymers, copolymers, blends, and composites of polymers.A copolymer is a polymer derived from more than one species of monomer.A polymer composite is a heterogeneous combination of two or morematerials, wherein the constituents are not miscible, and thereforeexhibit an interface between one another. A polymer blend is amacroscopically homogeneous mixture of two or more different species ofpolymer. Many polymers, copolymers, blends, and composites of polymersare radiolucent and do not appear during x-ray or other types ofimaging. Implants comprising such materials can provide a physician witha less obstructed view of the spine under imaging, than with an implantcomprising radiopaque materials entirely. However, the implant need notcomprise any radiolucent materials.

One group of biocompatible polymers is the polyaryletherketone groupwhich has several members including polyetheretherketone (PEEK), andpolyetherketoneketone (PEKK). PEEK is proven as a durable material forimplants, and meets the criterion of biocompatibility. Medical gradePEEK is available from Victrex Corporation of Lancashire, Great Britainunder the product name PEEK-OPTIMA. Medical grade PEKK is available fromOxford Performance Materials under the name

OXPEKK, and also from CoorsTek under the name BioPEKK. These medicalgrade materials are also available as reinforced polymer resins, suchreinforced resins displaying even greater material strength.

In an embodiment, the implant can be fabricated from PEEK 450G, which isan unfilled PEEK approved for medical implantation available fromVictrex. Other sources of this material include Gharda located inPanoli, India. PEEK 450G has the following approximate properties:

Property Value Density 1.3 g/cc Rockwell M 99 Rockwell R 126 TensileStrength 97 MPa Modulus of Elasticity 3.5 GPa Flexural Modulus 4.1 GPa

PEEK 450G has appropriate physical and mechanical properties and issuitable for carrying and spreading a physical load between the adjacentspinous processes. The implant and/or portions thereof can be formed byextrusion, injection, compression molding and/or machining techniques.

It should be noted that the material selected can also be filled.Fillers can be added to a polymer, copolymer, polymer blend, or polymercomposite to reinforce a polymeric material. Fillers are added to modifyproperties such as mechanical, optical, and thermal properties. Forexample, carbon fibers can be added to reinforce polymers mechanicallyto enhance strength for certain uses, such as for load bearing devices.In some embodiments, other grades of PEEK are available and contemplatedfor use in implants in accordance with the present invention, such as30% glass-filled or 30% carbon-filled grades, provided such materialsare cleared for use in implantable devices by the FDA, or otherregulatory body. Glass-filled PEEK reduces the expansion rate andincreases the flexural modulus of PEEK relative to unfilled PEEK. Theresulting product is known to be ideal for improved strength, stiffness,or stability. Carbon-filled PEEK is known to have enhanced compressivestrength and stiffness, and a lower expansion rate relative to unfilledPEEK. Carbon-filled PEEK also offers wear resistance and load carryingcapability.

As will be appreciated, other suitable similarly biocompatiblethermoplastic or thermoplastic polycondensate materials that resistfatigue, have good memory, are flexible, and/or deflectable, have verylow moisture absorption, and good wear and/or abrasion resistance, canbe used without departing from the scope of the invention. As mentioned,the implant can be comprised of polyetherketoneketone (PEKK). Othermaterial that can be used include polyetherketone (PEK),polyetherketoneetherketoneketone (PEKEKK), polyetheretherketoneketone(PEEKK), and generally a polyaryletheretherketone. Further, otherpolyketones can be used as well as other thermoplastics. Reference toappropriate polymers that can be used in the implant can be made to thefollowing documents, all of which are incorporated herein by reference.These documents include: PCT Publication WO 02/02158 A1, dated Jan. 10,2002, entitled “Bio-Compatible Polymeric Materials;” PCT Publication WO02/00275 A1, dated Jan. 3, 2002, entitled “Bio-Compatible PolymericMaterials;” and, PCT Publication WO 02/00270 A1, dated Jan. 3, 2002,entitled “Bio-Compatible Polymeric Materials.” Other materials such asBionate®, polycarbonate urethane, available from the Polymer TechnologyGroup, Berkeley, Calif., may also be appropriate because of the goodoxidative stability, biocompatibility, mechanical strength and abrasionresistance. Other thermoplastic materials and other high molecularweight polymers can be used.

Methods for Implanting Interspinous Implants

A minimally invasive surgical method for implanting an implant 7300 inthe cervical spine is disclosed and taught herein. In this method, asshown in FIG. 81, preferably a guide wire 7680 is inserted through aplacement network 7690 into the neck of the implant recipient. The guidewire 7680 is used to locate where the implant 7300 is to be placedrelative to the cervical spine, including the spinous processes. Oncethe guide wire 7680 is positioned with the aid of imaging techniques, anincision is made on the side of the neck so that an implant 7300 inaccordance with an embodiment of the present invention, can bepositioned in the neck thorough an incision and along a line that isabout perpendicular to the guide wire 7680 and directed at the end ofthe guide wire 7680. A frame 7302 of the implant 7300 is inserted intothe neck of the patient. The frame 7302 includes a distraction guide7306 extending from the proximal end of a central body 7304 and a firstwing 7330 extending from the distal end of the central body 7304. Theframe 7302 further includes a helical-shaped second wing 7360 extendingdistally from the distraction guide 7306 some distance along the centralbody 7304. Preferably during insertion, the distraction guide 7306pierces or separates the tissue without severing the tissue. The frame7302 can be arranged so that the second wing 7360 extending from thecentral body 7304 is in contact or near contact with the interspinousligament. The frame 7302 is then rotated in a direction so that thespiraling extension of the second wing 7360 “grows” and the frame 7302is urged forward such that the adjacent spinous processes fit within agroove between spiraled surfaces of the second wing 7360. The frame 7302is continuously rotated until the second wing 7360 has passed theadjacent spinous processes 2,4.

The frame 7302 can be further rotated until slots 7332,7334 of the firstwing 7330 are arranged as desired between the adjacent spinous processes2,4 of the targeted motion segment. Once the frame 7302 issatisfactorily positioned, a spacer 7320 can be mated with the frame7302 so that an upper portion 7322 and a lower portion 7324 of thespacer 7320 is received through the respective slot 7332,7334 of thefirst wing 7330 (or simply received over the central body 7304 forexample where the first wing 7330 extends from the spacer 7320 ratherthan extending form the central body 7304). The spacer 7320 can beinserted along a line that is generally collinear with the line overwhich the frame 7302 is inserted. The anatomy of the neck is such thatit is most convenient and minimally invasive to enter the neck from theside with respect to the frame 7302 and the spacer 7320.

Further, a minimally invasive surgical method for implanting an implant7300 in the lumbar spine is disclosed and taught herein. In this method,as shown in the flowchart of FIG. 82, preferably a unilateral incisioncan be made using a posterior-anterior approach. The unilateral incisioncan be made, for example, at a location some distance to the right of anaxis along the spinous process 2,4 (Step 7702). The incision can beenlarged, and a distraction tool can be positioned within the incisionso that the proximal end of the distraction tool can access an exposedside of the interspinous ligament 6. The distraction tool can be urgedthrough the interspinous ligament 6 and distracted, thereby distractingthe interspinous ligament 6 so as to receive the implant 7300 (Step7704). Once the interspinous ligament 6 is sufficiently distracted, thedistraction tool can be disengaged and removed from the incision.

Once the distraction tool has been removed from the incision, the frame7302 can be positioned at the dilated opening, and the distraction guide7306 of the frame 7302 can be urged through the dilated opening (Step7706). As above, the frame 7302 can be arranged so that the second wing7360 extending from the central body 7304 is in near contact with theinterspinous ligament 6. The frame 7302 is then rotated in direction sothat the spiraling extension of the second wing 7360 “grows”, and theframe 7302 urged forward such that the adjacent spinous processes 2,4fit within a groove between surface of the second wing 7360 (Step 7708).The frame 7302 is continuously rotated until the second wing 7360 haspassed the adjacent spinous processes 2,4. The frame 7300 can be furtherrotated until the slots 7332,7334 are arranged as desired between theadjacent spinous processes of the targeted motion segment. The frame7302 is free to rotate so that the load can be distributed more evenlyover the surface of the spinous processes. Once the frame 7302 issatisfactorily positioned, a spacer 7320 can be inserted with slots7322,7324 of a first wing 7330 extending from the distal end of thecentral body 7304 (or simply received over the central body for examplewhere the first wing extends from the spacer). The spacer 7320 can beinserted along a line that is generally collinear with the line overwhich the frame 7302 is inserted (Step 7710). The remaining tools can beremoved from the incision, and the incision can be closed. Preferablyduring insertion, the distraction end pierces or separates the tissuewithout severing the tissue (Step 7712). The foregoing description ofthe present invention have been presented for purposes of illustrationand description. It is not intended to be exhaustive or to limit theinvention to the precise forms disclosed. Many modifications andvariations will be apparent to practitioners skilled in this art. Theembodiments were chosen and described in order to best explain theprinciples of the invention and its practical application, therebyenabling others skilled in the art to understand the invention forvarious embodiments and with various modifications as are suited to theparticular use contemplated. It is intended that the scope of theinvention be defined by the following claims and their equivalents.

Interspinous Implant Having Slide-In Distraction Piece

FIG. 83 is a perspective end view of an alternative embodiment of animplant 8700 in accordance with the present invention. The implant 8700can include an initiating piece 8704 and a slide-in distraction piece8702 adapted to be slidably coupled with the initiating piece 8704.

The initiating piece 8704 and the slide-in distraction piece 8702, whenpositioned between adjacent spinous processes and coupled together, canresemble implants 7100 as described above with reference to FIGS. 7-23.For example, the implant 8700 of FIG. 83 includes a first wing 8730 at adistal end of the implant 8700, a fixed spacer 8720 extending from thefirst wing 8730, a second wing 8760 extending from the spacer 8720 sothat the spacer 8720 is disposed between the first wing 8730 and thesecond wing 8760, and a distraction guide 8710 at a proximal end 8716 ofthe implant 8700. FIG. 84A is a perspective view of the initiating piece8704. The initiating piece 8704 includes a slot 8784 within a lowersliding surface 8794 that extends through a substantial portion of thelength of the initiating piece 8704, the slot 8784 being adapted toreceive a rail 8782 of the slide-in distraction piece 8702. The slot8784 extends a length at least as long as the rail 8782 and preferablydoes not extend through the entire initiating piece 8704 so that thedistraction piece 8702 is prevented from sliding out of position in thedirection of insertion. As shown, the slot 8784 includes a flange 8785along the periphery of the slot 8784 to retain the rail 8782 within theslot 8784. The slot 8784 is thus shaped to substantially conform with a“T” shaped cross-section of the rail 8782 so that when the slide-indistraction piece 8702 is mated with the initiating piece 8704 and therail 8782 is seated within the slot 8784, relative movement between thedistraction piece 8702 and the initiating piece 8704 is limited orsubstantially blocked, except along the longitudinal axis 8725 in adirection opposite the direction of insertion. To limit or blockmovement along the longitudinal axis 8725 in a direction opposite thedirection of insertion, the slot 8784 can include a recess 8787 adaptedto receive a catch 8781 of the rail 8782 so that when the catch 8781passes over the recess 8787, the catch 8781 is extended, locking thedistraction piece 8702 in place, and limiting or blocking movement in adirection opposite insertion. Alternatively, the catch 8781 can beextendably associated with the slot 8784, while the recess 8787 isformed within the rail 8782 for receiving the catch 8781.

The initiating piece 8704 includes a lower distraction element 8714having a contact surface that tapers to the proximal end 8716 from aboveas well as below the proximal end 8716 so that the lower distractionelement 8714 has a “V” shape in cross-section along an axis of thespine. Such a geometry can ease implantation when compared with adistraction element 8714 that tapers to the proximal end only from below(or above) the proximal end 8716 by more evenly distributing a loadforce applied to the lower distraction element 8714 by the interspinousligament 6 during initial piercing and/or distraction of theinterspinous ligament 6. The initiating piece 8704 further includes alower portion 8734 of the first wing, a lower portion 8764 of the secondwing, and a lower portion 8724 of the spacer. In an embodiment, thelower portions 8734,8764,8724 can be integrally formed as the lowerdistraction element 8714, thereby avoiding discontinuities in a lowersliding surface 8794 of the initiation piece 8704. The lower slidingsurface 8794 of the initiating piece 8704 is substantially flat andpreferably smooth to ease receipt of the rail 8782 within the slot 8784.The lower sliding surface 8794 slopes upward relative to thelongitudinal axis 8725 from the distal end of the initiating piece 8704to the proximal end of the initiating piece 8704. The slope of the lowersliding surface 8794 causes variation in thickness of the lower portion8724 of the spacer from the distal end of the spacer to the proximal endof the spacer. This slope aids in the distraction of the spinousprocesses upon insertion of the distraction piece 8702. Referring againto FIG. 83, the contact surfaces of the implant 8700 include relativelysmooth transitions from the distraction guide 8710 to the second wing8760, and from the second wing 8760 to the spacer 8720. As described ingreater detail below, during implantation the initiating piece 8704 andthe distraction piece 8702 are positioned as separate, single pieces. Arelatively continuous surface with smooth transitions improves ease ofimplantation and minifies obstruction of the initiating piece 8704 andthe distraction piece 8702 by the adjacent spinous processes and/orrelated tissues. In contrast to implants as described with reference toFIGS. 7-23, it is preferable that the distraction piece 8702 and theinitiating piece 8704 have smoother transitions between the distractionguide 8710, the second wing 8760, and the spacer 8720, as suchtransitions even further lessen the obstruction to the movement of theimplant during implantation.

The lower portion 8734 of the first wing can further optionally includeone or more cavities 8770 for receiving prongs of an insertion tool. Asshown in FIGS. 84A through 84C, the initiating piece 8704 includes twocavities 8770 extending from the distal end of the initiating piece 8704toward the proximal end 8716, with one cavity 8770 being arranged oneach side of the lower portion 8734 of the first wing. Each cavity 8770can be sized to receive a prong of the insertion tool. The cavity 8770can further include a groove 8772 extending perpendicular to the cavity8770. Referring to FIGS. 84B and 84C, a prong 8795 of an insertion tool8794 can include, in an embodiment, a protrusion 8796 that fits withinthe groove 8772. When the prong is inserted into the cavity 8770 androtated approximately 90 degrees (FIG. 84C) so that the protrusion isrotated into the groove 8772, the prong is “locked” within the cavity8770. Once the prongs of the insertion tool are arranged in a lockedconfiguration, the implant 8700 can be releasably guided into positionbetween the adjacent spinous processes.

FIG. 85A is a posterior view of the initiating piece 8704 positionedadjacent to the interspinous ligament 6. As can be seen, the initiatingpiece 8704 has a maximum thickness T from the lower sliding surface 8794to the lower portion 8764 of the second wing. In a preferred embodiment,the maximum thickness T of the initiating piece 8704 is approximatelythe same as, or less than the thickness of the spacer 8720 when theinitiating piece 8704 and the distraction piece 8702 are mated and theimplant 8700 is positioned between the adjacent spinous processes 2,4.Referring to FIG. 85B, as the initiating piece 8704 is urged into theinterspinous ligament 6, the lower distraction element 8714 piercesand/or distracts the fibers of the interspinous ligament 6. As shown inFIG. 85C, the initiating piece 8704 is further urged through theinterspinous ligament 6 so that the lower portion 8764 of the secondwing passes between the adjacent spinous processes 2,4 but preferablydoes not distract the space between the adjacent spinous processes 2,4beyond the maximum distraction height of the spacer 8720. As shown inFIG. 85D, the initiating piece 8704 is further urged through theinterspinous ligament 6 so that the lower portion 8724 of the spacer isapproximately positioned between the adjacent spinous processes 2,4.Note that in other embodiments, the maximum thickness T from the lowersliding surface 8794 to the lower portion 8764 of the second wing can begreater than the ultimate thickness of the spacer 8720 so that when theinitiating piece 8704 is positioned between adjacent spinous processes2,4, the space between the spinous processes 2,4 is distracted to aheight greater than the distraction height of the spacer 8720. In suchembodiments, the second wing 8760 can potentially provide greater rangeof flexion motion (wherein the space between adjacent spinous processesincreases) while assuring that the movement of the implant 8700 will belimited or blocked in a direction opposite insertion by the second wing8760.

FIG. 86 is a flipped perspective end view of the slide-in distractionpiece 8702. The distraction piece 8702 includes a rail 8782 extendingover a substantial portion of the length of the distraction piece 8702,roughly corresponding to a length of the slot 8784 of the initiatingpiece 8704, within which the rail 8782 is adapted to be received. Theheight of the rail 8782 from the upper sliding surface 8792 to theflange 8783 of the rail 8782 approximately corresponds to the depth ofthe slot 8784 from the lower sliding surface 8794 to the bottom of theflange 8785 of the slot, so that when the rail 8782 is received withinthe slot 8784, the upper sliding surface 8792 of the distraction piece8702 is substantially flush with the lower sliding surface 8794. Inother embodiments, a gap can exist between the upper sliding surface8792 and the lower sliding surface 8794. As described above, the surfaceof the rail 8782 includes a catch 8781 arranged along the length of therail 8782 so that the catch 8781 roughly corresponds to the recess 8787disposed within the slot 8784. The catch 8781 can have a sloped leadingedge (from the proximal end to a distal end of the catch 8781) and canbe spring loaded, or otherwise biased so that the catch 8781 collapseswhen the distraction piece 8702 slides along the lower sliding surface8794 of the initiating piece 8704 and extends when passing over therecess 8787. The catch 8781 can have a trailing edge substantiallyperpendicular to the slot 8784 so that the catch 8781 resists movementof the distraction piece 8702 in a direction opposite insertion. Inother embodiments, the catch 8781 can be some other mechanism. Forexample, in an alternative embodiment, the catch 8781 can be a flexiblehinge and protrusion similar in operation to that described in FIGS.19A-20B. Still further the pieces 8702,8704 can be flexible enough thatthe catch 8781 is molded into the piece 8702,8704 and can snap into therecess 8787 in the other piece 8702,8704. The distraction piece 8702includes an upper distraction element 8712 having a contact surface thattapers so that the upper distraction element 712 has a ramp shape. Thedistraction piece 8702 further includes an upper portion 8732 of thefirst wing, an upper portion 8762 of the second wing, and an upperportion 8722 of the spacer. In an embodiment, the upper portions8732,8762,8722 can be integrally formed with the upper distractionelement 8712, thereby avoiding discontinuities in an upper slidingsurface 8792 of the distraction piece 8702. As with the lower slidingsurface 8790, the upper sliding surface 8792 of the distraction piece8702 is substantially flat and preferably smooth to ease positioning ofthe rail 8782 within the slot 8784. The upper sliding surface 8792slopes upward relative to the longitudinal axis 8725 from the distal endof the distracting piece 8702 to the proximal end of the distractionpiece 8702, the slope of the upper sliding surface 8792 beingsubstantially similar to the slope of the lower sliding surface 8794 sothat the two surfaces 8792,8794 are substantially parallel, and matewhen the rail 8782 is positioned within the slot 8784. The slope of theupper sliding surface 8792 causes variation in thickness of the upperportion 8722 of the spacer from the distal end of the spacer to theproximal end of the spacer so that the upper portion 8722 of the spaceris thicker at the distal end. When the distraction piece 8702 is matedwith the initiating piece 8704 so that the rail 8782 is seated withinthe slot 8784, the thickness of the spacer 8720 is approximately thesame across the length of the spacer 8720.

FIGS. 87A through 87D are a series of posterior views of the distractionpiece 8702 mating with the initiating piece 8704 so that the implant8700 is positioned between adjacent spinous processes 2,4 to support aload applied by the adjacent spinous processes 2,4 during an extensionmotion. As can be seen, the distraction piece 8702 is positioned so thatthe proximal end of the rail flange 8783 fits within the slot 8784. Thedistraction piece 8702 can then be urged toward the interspinousligament 6 so that the rail 8782 is further received within the slot8784. The thickness of the implant 8700 increases as the initiatingpiece 8704 is mated with the distraction piece 8702. FIG. 87Billustrates the distraction piece 8702 arranged so that the upperdistraction element 8782 is adjacent to the interspinous ligament 6. Asthe distraction piece 8702 is urged further toward the interspinousligament 6, the upper distraction element 8782 wedges between the lowersliding surface 8794 and the interspinous ligament 6 and/or the adjacentspinous processes 2,4, gradually distracting the interspinous ligament 6and the adjacent spinous processes 2,4 as the distraction piece 8702 isfurther urged in the direction of insertion. As shown in FIG. 87C, asthe upper portion 8762 of the second wing passes between the adjacentspinous processes 2,4, the space between the adjacent spinous processes2,4 is distracted beyond the maximum distraction height of the spacer8720. The distraction piece 8702 is further urged in the direction ofinsertion until the rail 8782 is seated within the slot 8784 and theupper portion 8762 of the second wing is arranged so that theinterspinous ligament 6 and/or adjacent spinous processes 2,4 aredisposed between the upper portion 8762 of the second wing and the upperportion 8732 of the first wing (see FIG. 87D). As the catch 8781 passesover the recess 8787, the catch 8781 extends into the recess 8787,locking the distraction piece 8702 in position, mated with theinitiation piece 8704.

Interspinous Implant Having Slide-In Distraction Piece

FIGS. 88A and 88B are perspective end views of an alternative embodimentof an implant 8800 in accordance with the present invention. The implant8800 can include an initiating piece 8804 and a slide-in distractionpiece 8802 that can be slidably coupled with the initiating piece 8804.The initiating piece 8804 and the slide-in distraction piece 8802, whenpositioned between adjacent spinous processes and coupled together asshown in FIG. 88B, has a saddle shape including a first wing 8830 and asecond wing 8860 that straddle one of the adjacent spinous processes.The implant 8800 approximates implants as shown above in FIGS. 7-23. Forexample, the implant 8800 includes the first wing 8830 at a distal endof the implant 8800, a fixed spacer 8820 extending from the first wing8830, the second wing 8860 extending from the spacer 8820 so that thespacer 8820 is disposed between the first wing 8830 and the second wing8860, and a distraction guide 8810 at a proximal end 8816 of the implant8800.

The initiating piece 8804 includes a slot 8884 within a lower slidingsurface 8886 that extends through a substantial portion of the length ofthe initiating piece 8804, the slot 8884 being adapted to receive a rail8882 of the slide-in distraction piece 8802. The slot 8884 canoptionally include a flange or some other structure to retain the rail8882 within the slot 8884. One of the slot 8884 and the rail 8882 canfurther optionally include a recess (not shown) adapted to receive acatch (not shown) of the other of the slot 8884 and the rail 8882 sothat when the catch passes over the recess, the catch is extended,locking the distraction piece 8802 in place, and limiting or blockingmovement along the longitudinal axis 8825.

As shown, the initiating piece 8804 includes a first tab 8894 extendingfrom the first wing 8834, the first tab 8894 including a firstperforation 8893. The distraction piece 8802 likewise includes a secondtab 8892 including a second perforation 8891 adapted to be aligned withthe first perforation 8893 so that when the slide-in distraction piece8802 is mated with the initiating piece 8804 and the rail 8882 is seatedwithin the slot 8884, the first perforation 8893 and the secondperforation 8891 are aligned and can be pegged together so that relativemovement between the distraction piece 8802 and the initiating piece8804 is limited or substantially blocked, in other embodiments, theinitiating piece 8804 and distraction piece 8802 need not include tabs8892,8894, for example where a catch and recess of the slot and rail isemployed. Further, where a first tab 8894 or other structure protrudesfrom the initiating piece 8804, the distraction piece 8802 can include aslot for receiving the tab 8894, rather than a second tab 8892 abuttingthe first tab 8894. As will be obvious to one of ordinary skill in theart, tabs having myriad different shapes and sizes can extend from oneor both of the initiating piece 8804 and the distraction piece 8802, andperforations having myriad different shapes and sizes can be formedwithin such tabs to limit relative movement between the initiating piece8804 and the distraction piece 8802. Further, myriad different lockingmechanisms (e.g., a tab and slot arrangement) can be employed with oneor both of the initiating pieces 8804 and the distraction piece 8802 tolimit relative movement. Embodiments of implants 8800 in accordance withthe present invention are not intended to be limited to thosearrangements shown in FIGS. 88A-89E.

The initiating piece 8804 includes a lower distraction element 8814having a contact surface that tapers to the proximal end 8816 from aboveas well as below the proximal end 8816 so that the lower distractionelement 8814 has a “V” shape in cross-section along an axis of thespine. The initiating piece 8804 further includes a first portion 8834of the first wing, the second wing 8860, and a lower portion 8824 of thespacer. In an embodiment, the lower portions 8824,8834 and the secondwing 8860 can be integrally formed with the lower distraction element8814, thereby avoiding discontinuities in a lower sliding surface 8888of the initiating piece 8804.

A relatively continuous sliding surface 8888 with smooth transitionsimproves ease of implantation and minifies obstruction of the initiatingpiece 8804 by the adjacent spinous processes and/or related tissues. Itis preferable that the initiating piece 8804 include smooth transitionsbetween the lower distraction element 8814, the second wing 8860, andthe lower portion 8824 of the spacer, as such transitions can increaseobstruction of implant movement during implantation. The lower slidingsurface 8888 of the initiating piece 8804 is substantially flat andpreferably smooth to ease receipt of the rail 8882 within the slot 8884.

As described above, the slide-in distraction piece 8802 includes therail 8882 extending over a substantial portion of the length of thedistraction piece 8802, roughly corresponding to a length of the slot8884 of the initiating piece 8804 within which the rail 8882 is adaptedto be received. The height of the rail 8882 from the upper slidingsurface 8886 approximately corresponds to the depth of the slot 8884 sothat when the rail 8882 is received within the slot 8884, the uppersliding surface 8886 of the distraction piece 8802 is substantiallyflush with the lower sliding surface 8888. In other embodiments, a gapcan exist between the upper sliding surface 8886 and the lower slidingsurface 8888. As described above, the surface of the rail 8882 caninclude a catch (or a recess) arranged along the length of the rail 8882so that the catch (or recess) roughly corresponds to the recess (orcatch) disposed within the slot 8884. In other embodiments, the rail8882 and slot 8884 need not include a catch and recess arrangement, butrather the initiating piece 8804 and the distraction piece 8802 can beheld in relative position along the longitudinal axis 8825 when thefirst and second holes 8891,8893 are pegged together. In still otherembodiments, some other mechanism can be used to limit or block relativemovement of the initiating piece 8804 and the distraction piece 8802.

The distraction piece 8802 further includes an upper distraction element8812, a second portion 8832 of the first wing and an upper portion 8822of the spacer. The upper distraction element 8812 has a contact surfacethat tapers at a proximal end of the distraction piece 8802 so that theupper distraction element 8812 has a ramp shape. The second portion 8832of the first wing can have a shape that roughly conforms to the shape ofthe first portion 8834 of the first wing so that when the distractionpiece 8802 is coupled to the initiating piece 8804, the first and secondportions 8832,8834 form a first wing 8830, as shown in FIG. 88B. Theupper portion 8822 of the spacer can have a thickness greater or lessthan that of the lower portion 8824 of the spacer. As shown, the upperportion 8822 is thicker than the lower portion 8824. By minifying thethickness of the lower portion 8824, distraction of the adjacent spinousprocesses during implantation of the initiation piece 8804 can beminified to cause less distraction at the surgical site by the secondwing 8860 as the second wing 8860 is urged between the adjacent spinousprocesses. Alternatively, a plurality of distraction pieces 8802 can beprovided each having an upper portion 8822 of the spacer having adifferent thickness. Thus the doctor can select the appropriatedistraction piece 8802 for the amount of distraction desired. As withthe lower sliding surface 8888, the upper sliding surface 8886 of thedistraction piece 8802 is substantially flat and preferably smooth toease positioning of the rail 8882 within the slot 8884. Embodiments ofsystems in accordance with the present invention can include ainitiating piece 8804 and a plurality of distraction pieces 8802, thedistraction pieces 8802 having a variety of thicknesses. In such asystem, a distraction piece 8802 can be chosen so that the overallspacer 8820 thickness is suitable for the patient and the motion segmenttargeted.

FIG. 89A is a posterior view of the initiating piece 8804 positionedadjacent to the interspinous ligament 6. As can be seen, the initiatingpiece 8804 has a maximum thickness from the lower sliding surface 8888to the second wing 8860. As the initiating piece 8804 is urged into theinterspinous ligament 6, the lower distraction element 8814 piercesand/or distracts the fibers of the interspinous ligament 6. As shown inFIG. 89B, the initiating piece 8804 is further urged through theinterspinous ligament 6 so that the second wing 8860 passes between theadjacent spinous processes 2,4 and can distract the space between theadjacent spinous processes 2,4 to accommodate the second wing 8860. Thedistraction of the space between the adjacent spinous processes isreduced by positioning the initiating piece 8804 prior to coupling thedistraction piece 8802 to the initiating piece 8804. Referring to FIG.89C, the initiating piece 8804 is further urged through the interspinousligament 6 so that the lower portion 8824 of the spacer is positionedbetween the adjacent spinous processes 2,4. The second wing 8860 and thefirst portion 8834 of the first wing straddle the lower spinous process4. Once the initiating piece 8804 is properly positioned, the rail 8882of the distracting piece 8802 can be positioned within the distal end ofthe slot 8884, as shown in FIG. 89D. The distraction piece 8804 can thenbe urged along the lower sliding surface 8888 so that the upperdistraction element 8812 distracts the space between the adjacentspinous processes. As shown in FIG. 89E, the initiating piece 8804 isfurther urged along the lower sliding surface 8888 until the distractionpiece 8802 is mated with the initiating piece 8804.

Materials for Use in Implants of the Present Invention

In some embodiments, the implant can be fabricated from medical grademetals such as titanium, stainless steel, cobalt chrome, and alloysthereof, or other suitable implant material having similar high strengthand biocompatible properties. Additionally, the implant can be at leastpartially fabricated from a shape memory metal, for example Nitinol,which is a combination of titanium and nickel. Such materials aretypically radiopaque, and appear during x-ray imaging, and other typesof imaging. Implants in accordance with the present invention, and/orportions thereof can also be fabricated from somewhat flexible and/ordeflectable material. In these embodiments, the implant and/or portionsthereof can be fabricated in whole or in part from medical gradebiocompatible polymers, copolymers, blends, and composites of polymers.A copolymer is a polymer derived from more than one species of monomer.A polymer composite is a heterogeneous combination of two or morematerials, wherein the constituents are not miscible, and thereforeexhibit an interface between one another. A polymer blend is amacroscopically homogeneous mixture of two or more different species ofpolymer. Many polymers, copolymers, blends, and composites of polymersare radiolucent and do not appear during x-ray or other types ofimaging. Implants comprising such materials can provide a physician witha less obstructed view of the spine under imaging, than with an implantcomprising radiopaque materials entirely. However, the implant need notcomprise any radiolucent materials.

One group of biocompatible polymers are the polyaryletherketone groupwhich has several members including polyetheretherketone (PEEK), andpolyetherketoneketone (PEKK). PEEK is proven as a durable material forimplants, and meets the criterion of biocompatibility. Medical gradePEEK is available from Victrex Corporation of Lancashire, Great Britainunder the product name PEEK-OPTIMA. Medical grade PEKK is available fromOxford Performance Materials under the name OXPEKK, and also fromCoorsTek under the name BioPEKK. These medical grade materials are alsoavailable as reinforced polymer resins, such reinforced resinsdisplaying even greater material strength. In an embodiment, the implantcan be fabricated from PEEK 450G, which is an unfilled PEEK approved formedical implantation available from Victrex. Other sources of thismaterial include Gharda located in Panoli, India. PEEK 450G has thefollowing approximate properties:

Property Value Density 1.3 g/cc Rockwell M 99 Rockwell R 126 TensileStrength 97 MPa Modulus of Elasticity 3.5 GPa Flexural Modulus 4.1 GPa

PEEK 450G has appropriate physical and mechanical properties and issuitable for carrying and spreading a physical load between the adjacentspinous processes. The implant and/or portions thereof can be formed byextrusion, injection, compression molding and/or machining techniques.It should be noted that the material selected can also be filled.Fillers can be added to a polymer, copolymer, polymer blend, or polymercomposite to reinforce a polymeric material. Fillers are added to modifyproperties such as mechanical, optical, and thermal properties. Forexample, carbon fibers can be added to reinforce polymers mechanicallyto enhance strength for certain uses, such as for load bearing devices,in some embodiments, other grades of PEEK are available and contemplatedfor use in implants in accordance with the present invention, such as30% glass-filled or 30% carbon-filled grades, provided such materialsare cleared for use in implantable devices by the FDA, or otherregulatory body. Glass-filled PEEK reduces the expansion rate andincreases the flexural modulus of PEEK relative to unfilled PEEK. Theresulting product is known to be ideal for improved strength, stiffness,or stability. Carbon-filled PEEK is known to have enhanced compressivestrength and stiffness, and a lower expansion rate relative to unfilledPEEK. Carbon-filled PEEK also offers wear resistance and load carryingcapability.

As will be appreciated, other suitable similarly biocompatiblethermoplastic or thermoplastic polycondensate materials that resistfatigue, have good memory, are flexible, and/or deflectable, have verylow moisture absorption, and good wear and/or abrasion resistance, canbe used without departing from the scope of the invention. As mentioned,the implant can be comprised of polyetherketoneketone (PEKK). Othermaterial that can be used include polyetherketone (PEK),polyetherketoneetherketoneketone (PEKEKK), polyetheretherketoneketone(PEEKK), and generally a polyaryletheretherketone. Further, otherpolyketones can be used as well as other thermoplastics. Reference toappropriate polymers that can be used in the implant can be made to thefollowing documents, all of which are incorporated herein by reference.These documents include: PCT Publication WO 02/02158 A1, dated Jan. 10,2002, entitled “Bio-Compatible Polymeric Materials;” PCT Publication WO02/00275 A1, dated Jan. 3, 2002, entitled “Bio-Compatible PolymericMaterials;” and, PCT Publication WO 02/00270 A1, dated Jan. 3, 2002,entitled “Bio-Compatible Polymeric Materials.” Other materials such asBionate®, polycarbonate urethane, available from the Polymer TechnologyGroup, Berkeley, Calif., may also be appropriate because of the goodoxidative stability, biocompatibility, mechanical strength and abrasionresistance. Other thermoplastic materials and other high molecularweight polymers can be used.

It is to be understood that embodiments in accordance with the presentinvention can be constructed without a pliant material. It is also to beunderstood that the embodiments in accordance with the present inventioncan have other dimensions

Methods for Implanting Interspinous Implants

In other embodiments of methods in accordance with the presentinvention, the implant can include an initiating piece 8704 and adistraction piece 8702, such as described above in FIGS. 83-87D. In suchembodiments, as shown in FIG. 90, preferably a guide wire 80 is insertedthrough a placement network or guide 90 into the neck of the implantrecipient (as shown and described above). Once the guide wire 80 ispositioned with the aid of imaging techniques, an incision is made onthe side of the neck so that an initiating piece 8704 of the implant8700 can be positioned in the neck thorough an incision and along a linethat is about perpendicular to the guide wire 80 and directed at the endof the guide wire. The initiating piece 8704 can include a lowerdistraction element 8714, a lower portion 8764 of the second wing, alower portion 8724 of the spacer, and a lower portion 8734 of the firstwing. The implant 8700 is inserted into the neck of the patient, betweenadjacent spinous processes. Preferably during insertion, the lowerdistraction element 8714 pierces or separates the tissue withoutsevering the tissue, and the implant 8700 is positioned so that theupper portion 8724 of the spacer is disposed between the adjacentspinous processes.

Once the initiating piece 8704 is satisfactorily positioned, adistracting piece 8702 can be inserted along a line that isapproximately collinear with the line over which the initiating piece8704 is inserted, but positioned so that a rail 8782 of the distractingpiece 8702 mates with a slot 8784 of the initiating piece 8704. Theanatomy of the neck is such that it is most convenient and minimallyinvasive to enter the neck from the side with respect to the implant8700. The distracting piece 8702 can be mated to the initiating piece8704 through an interference fit, or using a catch 8781 and recess 8787as described above, alternatively by connecting the distracting piece8704 with the initiating piece 8702 using a fastener, or by some otherdevice, as described above. It is to be understood that the embodimentdescribed herein can be used between any of the spinous processes of thespine.

In other embodiments of methods in accordance with the presentinvention, the implant can include an initiating piece 8804 and adistraction piece 8802, such as described above in FIGS. 88A-89E. Insuch embodiments, as shown in FIG. 91, preferably a guide wire 80 isinserted through a placement network or guide 90 into the neck of theimplant recipient (as shown and described above). Once the guide wire 80is positioned with the aid of imaging techniques, an incision is made onthe side of the neck so that an initiating piece 8804 of the implant8800 can be positioned in the neck thorough an incision and along a linethat is about perpendicular to the guide wire 80 and directed at the endof the guide wire. The initiating piece 8804 can include a lowerdistraction element 8814, the second wing 8860, a lower portion 8824 ofthe spacer, and a lower portion 8834 of the first wing. The implant 8800is inserted into the neck of the patient, between adjacent spinousprocesses. Preferably during insertion, the lower distraction element8814 pierces or separates the tissue without severing the tissue, andthe implant 8800 is positioned so that the upper portion 8824 of thespacer is disposed between the adjacent spinous processes. Once theinitiating piece 8804 is satisfactorily positioned, a distracting piece8802 can be inserted along a line that is approximately collinear withthe line over which the initiating piece 8804 is inserted, butpositioned so that a rail 8882 of the distracting piece 8802 mates witha slot 8884 of the initiating piece 8804. The anatomy of the neck issuch that it is most convenient and minimally invasive to enter the neckfrom the side with respect to the implant 8800. The distracting piece8802 can be mated to the initiating piece 8804, by pegging the first andsecond perforations 8891,8893, through an interference fit, or using acatch 8881 and recess 8887 as described above, or, alternatively byconnecting the distracting piece 8804 with the initiating piece 8802using a fastener, or by some other device, as described above.

The foregoing description of the present invention have been presentedfor purposes of illustration and description. It is not intended to beexhaustive or to limit the invention to the precise forms disclosed.Many modifications and variations will be apparent to practitionersskilled in this art. The embodiments were chosen and described in orderto best explain the principles of the invention and its practicalapplication, thereby enabling others skilled in the art to understandthe invention for various embodiments and with various modifications asare suited to the particular use contemplated. It is intended that thescope of the invention be defined by the following claims and theirequivalents.

1. An apparatus, comprising: a central body having an elongate memberand a retention member, a first portion of the retention member beinganchored and rotationally fixed to the elongate member, at least aportion of the elongate member configured to be disposed between a pairof adjacent spinous processes; a movable member anchored androtationally fixed to a second portion of the retention member of thecentral body, the retention member being collapsed from a firstconfiguration to a second configuration different than the firstconfiguration when the movable member is moved proximally relative tothe elongate member of the central body; and the first and secondportions of the retention member being anchored and rotationally fixedto the elongate member and the movable member respectively when theretention member is in both the first and second configurations.
 2. Theapparatus of claim 1, wherein the second portion of the retention memberof the central body is different than the first portion of the retentionmember of the central body.
 3. The apparatus of claim 1, wherein atleast a portion of the movable member is configured to slidably movewithin an interior portion of the central body.
 4. The apparatus ofclaim 1, wherein the movable member has a distal portion and a proximalportion, the second portion of the retention member of the central bodyis anchored and rotationally fixed to the distal portion of the movablemember.
 5. The apparatus of claim 1, wherein the elongate member has adistal portion and a proximal portion, the first portion of theretention member of the implant is anchored and rotationally fixed tothe distal portion of the central body.
 6. The apparatus of claim 1,wherein a length of the retention member when the retention member is inthe first configuration is different than a length of the retentionmember when the retention member is in the second configuration.
 7. Theapparatus of claim 1, further comprising: a spacer configured to becoupled to the central body so as to extend through a sagittal planedefined by the adjacent spinous processes after the elongate member ofthe central body is disposed between the pair of adjacent spinousprocesses.
 8. The apparatus of claim 1, further comprising: a spacerconfigured to be coupled to the central body so as to extend through asagittal plane defined by the adjacent spinous processes after theelongate member of the central body is disposed between the pair ofadjacent spinous processes, a central portion of the spacer configuredto define a minimal extension between the pair of adjacent spinousprocesses.
 9. The apparatus of claim 1, wherein the retention member isspiraled.
 10. The apparatus of claim 1, wherein the retention member isa spiraled member configured to move the elongate member of the centralbody relative to the pair of adjacent spinous processes when at least aportion of the spiraled member is rotated between the pair of adjacentspinous processes.
 11. The apparatus of claim 1, wherein the centralbody is a first central body having a proximal end portion configured tomovably mate with a second central body.
 12. The apparatus of claim 1,wherein the retention member has a helical portion defining a gap whenthe retention member is in the first configuration, the helical portionbeing devoid of a gap when the retention member is in the secondconfiguration.
 13. The apparatus of claim 1, wherein the retentionmember has a helical portion defining a gap, a size of the gap when theretention member is in the first configuration being greater than awidth of a spinous process from the pair of adjacent spinous processes,a size of the gap when the retention member is in the secondconfiguration being less than a width of the spinous process from thepair of adjacent spinous processes.
 14. The apparatus of claim 1,wherein a size of the retention member along an axis substantiallynormal to a longitudinal axis of the central body when the retentionmember is in the first configuration is substantially equal to a size ofthe retention member along the axis substantially normal to thelongitudinal axis of the central body when the retention member is inthe second configuration.
 15. The apparatus of claim 1, wherein theretention member is configured to be moved through a space between thepair of adjacent spinous processes when the retention member is in thefirst configuration, the retention member has a diameter greater than asize of the space between the pair of adjacent spinous processes whenthe retention member is in the first configuration.
 16. The apparatus ofclaim 1, wherein the first portion of the retention member is configuredto contact a first spinous process from the pair of adjacent spinousprocesses when a portion of the elongate member is disposed between thepair of adjacent spinous processes and when the retention member is inthe second configuration.
 17. An apparatus, comprising: an implanthaving a retention portion and a central portion, at least a portion ofthe central portion configured to be disposed between a pair of adjacentspinous processes; the implant further having a wing; wherein thecentral portion is disposed between the wing and the retention portion;the retention portion configured to be inserted between the pair ofadjacent spinous processes when in a first configuration, the retentionportion configured to be collapsed from the first configuration to asecond configuration, the retention portion configured to limit lateralmovement of the implant relative to the pair of adjacent spinousprocesses when in the second configuration, a distance from alongitudinal axis of the implant to an edge of the retention memberbeing substantially the same in the first configuration and the secondconfiguration; wherein the wing remains in the same position relative tothe central portion as the retention member moves between the first andsecond configurations; wherein a longitudinal length of the implant isdifferent when the retention portion is in the first configuration thanwhen the retention portion is in the second configuration.
 18. Theapparatus of claim 17, wherein the distance is along an axissubstantially parallel to a midline axis defined by the adjacent spinousprocesses when the central portion of the implant is disposed betweenthe pair of adjacent spinous processes.
 19. The apparatus of claim 17,wherein the implant is a first implant, the apparatus furthercomprising: a second implant configured to be coupled to the firstimplant so as to extend through a sagittal plane defined by the adjacentspinous processes after the central portion of the first implant isdisposed between the pair of adjacent spinous processes, a centralportion of the second implant configured to define a minimal extensionbetween the pair of adjacent spinous processes.
 20. The apparatus ofclaim 17, wherein the central portion of the implant is configured to bemoved distally relative to the pair adjacent spinous processes along alateral axis defined by the pair of adjacent spinous processes when theretention portion of the implant is disposed between the pair ofadjacent spinous processes in the first configuration, and when theretention portion is rotated about the lateral axis defined by the pairof adjacent spinous processes.
 21. The apparatus of claim 17, whereinthe retention portion is spiraled.
 22. The apparatus of claim 17,wherein the retention portion has a helical member defining a gap whenthe retention portion is in the first configuration, the helical memberbeing devoid of a gap when the retention portion is in the secondconfiguration.
 23. The apparatus of claim 17, when retention portion hasa helical member, a first surface of the helical member spaced apartfrom a second surface of the helical member when the retention portionof the implant is in the first configuration, the first surface of thehelical member in contact with the second surface of the helical memberwhen the retention portion of the implant is in the secondconfiguration.
 24. The apparatus of claim 17, wherein a first portion ofthe retention portion is configured to contact a first spinous processfrom the pair of adjacent spinous processes when a portion of thecentral portion is disposed between the pair of adjacent spinousprocesses and when the retention portion is in the second configuration.25. An apparatus, comprising: an implant having a retention portion anda central portion, at least a portion of the central portion configuredto be disposed between a pair of adjacent spinous processes; the implantfurther having a wing: wherein the central portion is disposed betweenthe wing and the retention portion; the retention portion configured tobe inserted between the pair of adjacent spinous processes when in afirst configuration, the retention portion configured to be collapsedfrom the first configuration to a second configuration, the retentionportion configured to limit lateral movement of the implant relative tothe pair of adjacent spinous processes when in the second configuration,a distance from a longitudinal axis of the implant to an edge of theretention member being substantially the same in the first configurationand the second configuration; wherein the wing remains in the sameposition relative to the central portion as the retention member movesbetween the first and second configurations; wherein the implant isconfigured such that a distal end of the retention portion of theimplant is moved proximally relative to a proximal end of the retentionportion when the retention portion of the implant is collapsed from thefirst configuration to the second configuration.
 26. An apparatus,comprising: an implant having a retention portion and a central portion,at least a portion of the central portion configured to be disposedbetween a pair of adjacent spinous processes; the implant further havinga wing; wherein the central portion is disposed between the wing and theretention portion; the retention portion configured to be insertedbetween the pair of adjacent spinous processes when in a firstconfiguration, the retention portion configured to be collapsed from thefirst configuration to a second configuration, the retention portionconfigured to limit lateral movement of the implant relative to the pairof adjacent spinous processes when in the second configuration, adistance from a longitudinal axis of the implant to an edge of theretention member being substantially the same in the first configurationand the second configuration; wherein the wing remains in the sameposition relative to the central portion as the retention member movesbetween the first and second configurations; a movable member having afirst portion slidably disposed within the central portion of theimplant and a second portion coupled to the retention portion of theimplant; wherein the implant is configured such that the retentionportion of the implant is collapsed from the first configuration to thesecond configuration when the first portion of the movable member ismoved proximally within the central portion of the implant.